Curtis’s Speed GED » Number Sense http://www.passged.com/student_blogs/curtis My Fast and Smart Road to the GED Fri, 02 Dec 2011 15:00:06 +0000 en hourly 1 http://wordpress.org/?v=3.2.1 GED Election Practice Question… Answered http://www.passged.com/student_blogs/curtis/2011/12/01/ged-election-practice-question-answered/ http://www.passged.com/student_blogs/curtis/2011/12/01/ged-election-practice-question-answered/#comments Thu, 01 Dec 2011 20:18:40 +0000 Curtis http://www.passged.com/student_blogs/curtis/2008/01/07/ged-election-practice-question-answered/ Yeah, everyone says there ain’t math in everyday life like in the GED math test, but look at how math makes a difference in who gets to be president? That’s a big deal… and you can see the same sort of math on the GED. So, here’s the question… Here’s some info, just about a few states, so you can see what’s what:
Alabama…9 electoral college votes…4.5 million people
Alaska…3 electoral college votes…0.6 million people
Arizona…10 electoral college votes…5.1 million people
Arkansas…6 electoral college votes…2.7 million people

So, here’s your GED test practice question…

Alabama: Democrat = 2.2 million votes
Republican = 2.3 million votes

Alaska: Democrat = .5 million votes
Republican = .1 million votes

Arizona: Democrat = 2.3 million votes
Republican = 2.8 million votes

Arkansas: Democrat = 1.7 million votes
Republican = 1 million votes

GED Question 1: What’s the total popular vote for each candidate?

This is an easy one, right? On the GED they got this thing called “number sense,” and that just means knowin’ what kind of math to use and bein’ able to get the numbers to do what got to do. So, here, all you got to do is add up the “popular vote”…that’s the total people that voted…for each candidate:

Democratic = 2.2 + .5 + 2.3 + 1.7 = 6.7 million people

I can totally do that in my head… cuz 2.2 + 2.3 = 4.5, plus .5 = 5 even, plus 1.7 = 6.7

Republican = 2.3 + .1 + 2.8 + 1 = 6.2 million people

Faster you can do this kinda math on the GED, the better you’ll do. So, I can say, 2.8 + 2.3 would be 5.1, plus .1 is 5.2, plus 1 even is 6.2. By the popular vote, the Democrat wins by about half a million. But in real life, it don’t go that way… so there’s the second GED question…

GED Question 2: What’s the total electoral vote for each candidate?

Electoral votes goes by states. Each state got so many of ‘em, an the people in the state vote to see who gets their state’s votes. So, it’s like the state votes for the president instead of the people votin’ for the president. That’s good background for the social studies GED. But it’s also good for the math GED, cuz you got to use your number sense. In each state, the person who gets most votes in that state, gets the electoral college votes, like this:

Alabama: Republican gets more votes = 9 electoral college votes

Alaska: Democrat gets more votes = 3 electoral college votes

Arizona: Republican gets more votes = 10 electoral college votes

Arkansas: Democrat gets more votes = 6 electoral college votes

Republican = 19 electoral college votes

Democrat = 9 electoral college votes

Landslide victory for the Republican! But wait… more people voted for the Dem… what gives?

GED Question 3: If these were all the states, who wins?

Easy… the popular vote don’t count, only the electoral college votes, so the Republican wins. These numbers are all made up, but do you see how that math works? Math is about manipulating numbers, right? So how you calculate a vote with math can change the outcome… These GED skills is things you can use in life.

The election fun is just gettin’ started, with Obama and Huckabee winning in Iowa and New Hampshire bein’ the next contest… so I’ll think of some more GED math for these here elections.

To find out more about the GED test and GED test preparation, visit The GED Academy at passGED.com.

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GED Math: Getting Your Street Math http://www.passged.com/student_blogs/curtis/2011/02/21/ged-math-getting-your-street-math/ http://www.passged.com/student_blogs/curtis/2011/02/21/ged-math-getting-your-street-math/#comments Tue, 22 Feb 2011 00:26:24 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=7 You know, one of the things that helps me out with all this GED math is doin’ estimatin’ in my head. I figured this all comes from figurin’ out how much stuff costs, you know. It all comes back to the cash.

So try this… next time you go get groceries, keep track in your head how much you’re spending. Try to estimate the costs… you know, $1.50 instead of $1.38… to make it easier to add together the amounts in your head. When you get in the checkout line, see how close you were, and try to get closer each time you buy groceries. Maybe start with just buyin’ a few things, then more each time. That way, you can build up your street math, just like I got in my head.

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GED Math: Dyscalculia http://www.passged.com/student_blogs/curtis/2009/12/16/ged-math-dyscalculia/ http://www.passged.com/student_blogs/curtis/2009/12/16/ged-math-dyscalculia/#comments Wed, 16 Dec 2009 18:12:13 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=157 What up everyone?

I been hearing about this thing lately called dyscalculia. I ain’t never heard of that before, but I have heard ’bout dyslexia. So, I figured the two were linked. I looked it up, and it turns out they are. Discalculia’s kinda like dyslexia with numbers. Only it’s more than that. It effects people’s sense of time and space and all that. Check out this list of symptoms.

Anyway, it kinda helped me understand people a little better. Like, when I add up numbers, I just get it, you know? But if I think about it like dyslexia, that’s somethin’ I can understand. Sometimes I just don’t get words. It’s like they all a jumble, and I gotta slow down and really pay attention. But there’s people out there who can just scan a page real quick and tell you everything that be on it. Maybe those same people can’t get numbers like I can, right?

So, maybe some people got discalculia without knowing it. It’s not well known, like dyslexia. Maybe someone famous gotta have it first before the public notices it. For now, there’s a cool site called Dyscalculia Forum that’s got a lot of info and other people who’ve got dyscalculia. They help each other out and offer up solutions they’ve found that helps them remember numbers.

Mostly, it seems like if someone’s got problems in one area, they probably are pretty good at somethin’ else. So, if you’re having problems with numbers, you gotta think about somethin’ else you’re good at, like words, art, or music. For instance, there’s ten numbers total, right? Maybe you can assign a color to each number. Like this:

0123456789

So, 0 is black ’cause it’s nothin’ so it’s not a color too, right? Then I started with pink, red, orange, yellow, green, teal, blue, purple, violet. Someone who’s real artistic might be able to remember the order of colors easier than the order of numbers. And maybe they can remember mental multiplication easier with colors. So instead of 7×8=56, they might think, blue x purple = green-teal.

I don’t think in colors myself, and that’s a pretty wild example, but it shows how you might get started thinkin’ about different ways to understand numbers. Here’s some other ways to think about numbers differently:

  • Read problems aloud and talk through the answers (sometimes hearing yourself problem solve is helpful).
  • When learning a new concept, make sure you understand it well enough to teach it back before moving on.
  • Try to visualize the Math problem. If the problem is about a house, draw the house, then add in the dimensions as the problem goes along.
  • Practice estimating as a way to solve problems.
  • Don’t be afraid to count on your fingers.
  • Use scratch paper! You may remember things better by writing them down and working through the problem on paper and not in your head.
  • Try using colored pencils for emphasis or to differentiate problems.
  • Memorize Math facts to music or a beat (Mary had a little lamb, etc.).
  • If you are doing a “non story problem” type of Math problem, make up a story for it. If you can relate the problem to real life, it may be easier to solve.

When it comes down to it, though, everyone’s different, so you gotta figure out a method that works for you. Check out these 8 different types of intelligences that Dr. Howard Gardner discovered. Maybe you can figure out which one fits with you and come up with your own strategy for understanding Math better.

  1. Linguistic and verbal intelligence: good with words
  2. Logical intelligence: good with math and logic
  3. Spatial intelligence: good with pictures
  4. Body/movement intelligence: good with activities
  5. Musical intelligence: good with rhythm
  6. Interpersonal intelligence: good with communication
  7. Intrapersonal intelligence: good with analyzing things
  8. Naturalist intelligence: good with understanding natural world

For more information about the GED test and GED test preparation, visit the GED Academy at  http://www.passGED.com.

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GED Math: Thanksgiving http://www.passged.com/student_blogs/curtis/2009/11/25/ged-math-thanksgiving/ http://www.passged.com/student_blogs/curtis/2009/11/25/ged-math-thanksgiving/#comments Wed, 25 Nov 2009 18:05:33 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=152 Thanksgiving’s comin’ up ’round the corner, so I figured I put up a little something about turkey and stuff. Check it out:

A 12lb turkey at the grocery store costs $13.50 and feeds 8 people. A pint of potato salad costs $3.50 per pint, and one pint can feeds about 3 people. A large can of yams is on sale for $4, and that feeds 5 people. Finally, a pumpkin pie feeds about 6 people and costs $4.99. Paula is shopping for Thanksgiving and is planning on having 16 guests, including herself. How much will it cost to make sure there is enough of each item for everyone?

This is the kinda question that shows how Math can be practical for everyday use, right? I’ve never bought thanksgiving dinner myself, but sometimes you get some friends comin’ over for some pizza and beers, and you gotta know how much to buy for everyone (and how much you charge them at the door).

So first thing I gotta do here is write out all the information, to make sure I get what they’re askin’.

Paula’s got 16 people comin’ for dinner. First I gotta break down the problem and see how many people each type of food feeds. I’ll make a quick list.

12lb Turkey – $13.50 – Feeds 8

Potato Salad – $3.50 – Feeds 3

Yams – $4.00 – Feeds 5

Pumpkin – $4.99 – Feeds 6

Once I got all this information laid out, it’s pretty simple to figure things out:

The turkey feeds 8, and we know that 8 × 2 is 16, so that’s easy. She needs 2 turkeys. That’s $27.

A pint of potato salad feeds 3, so she’d need 6 pints to feed 16 since 3 × 6 = 18. 3 × 5 is only 15, and that wouldn’t be enough salad for everyone. So then I gotta times 6 × 3.50 to get $21

She’d need 4 cans of yams, so that’s $16, and 3 pumpkin pies. That’s $14.97. Usually I’d just round the pie up to $5, which makes it an easy $15, but since we gotta have the exact answer here, I can’t do that. So adding up all those answers, I got $78.97. Damn, that’s expensive. And it ain’t even including no drinks. See, that’s why I never have no Thanksgiving at my place. Gotta clean it all up too, no way. I just go out to a buffet and pay like ten bucks for all I can eat. That’s how you do it, yo.

Have a good Thanksgiving y’all.

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com

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GED Math: Taking a Closer Look http://www.passged.com/student_blogs/curtis/2009/11/09/ged-math-taking-a-closer-look/ http://www.passged.com/student_blogs/curtis/2009/11/09/ged-math-taking-a-closer-look/#comments Tue, 10 Nov 2009 02:14:43 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=135 S’up y’all. Ready for some more GED Math?

I been thinkin’ about how sometimes we think we know the answer without looking at the whole problem, you know? Check this out.

Super Subs Inc. is planning on hiring new employees for the summer. They want to make sure their new employees are available to work on the busiest day of the week. Below is a chart of their four different stores, and how many sub sandwiches they sold at each store the previous week. According to this chart, which day will the new hires most likely need to work?

chart_sub_sandwiches


1. Wednesday

2. Thursday

3. Friday

4. Saturday

5. Sunday


I usually like takin’ short cuts, right? But you can’t depend on short cuts. You gotta make sure you’re right, or you’ll get taken for a ride.

First, we gotta make sure we know what we’re lookin’ for. The question’s askin’ what day is most important for new employees to work. The most important day is when they’re sellin’ the most, right? So, next thing is to check out is on which day they’re sellin’ the most subs. When I first look at this chart, I just scan through and see that in the first row, for store “A,” they’re sellin’ the most on Friday. Bam, that’s the answer, right? Wrong. Scannin’ a chart real quick is a good strategy to get information, but you always gotta double check. Check out stores B-D. They’re sellin’ more subs on Saturday. Since there’s three stores that sell more on Saturday, and only one that sells more on Friday, now we can make a better guess that Saturday’s the answer we’re lookin’ for. But let’s double check again to make sure.

Add up all the subs sold on Friday at all the stores. It’s 489. And Saturday is 560. In fact, you don’t even need to really add all those up straight up, you can just estimate and get 490 for Friday and 570 for Saturday. See, we were right, even with simple estimation, we can see they sell way more subs on Saturday. Since we scanned first, then double checked, we can be sure we got the right answer now. It’s 4. Saturday.

So check out this next question.


Super Subs Inc. may need to shut down a store due to the bad economy. According to the chart, which store would they most likely shut down?
1. Store A

2. Store B

3. Store C

4. Store D

5. None of the Stores


Remember, we can’t just take a guess lookin’ at the first column of numbers. What y’all think the answer is?

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com

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What Can GED Math Do for You? http://www.passged.com/student_blogs/curtis/2009/05/13/what-can-ged-math-do-for-you/ http://www.passged.com/student_blogs/curtis/2009/05/13/what-can-ged-math-do-for-you/#comments Wed, 13 May 2009 17:39:51 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=122 Yo, one thing I know, math is part of life. Y’all pay yo’ bills every month, right? Gotta balance income and outgo? Math, right? Not jus’ that, but thinkin’ about what you wanna do after you get yo’ GED? Best payin’ jobs, all about math. Construction, design, computers, fightin’ fires, all of ‘em use math one way or another. Not to mention trackin’ all yo’ favorite sports teams. I got dat down. Found this article, ’bout eighth graders learnin’ all about how math leads on to better careers… somethin’ we all could learn: Math Is Everywhere

Plus, remember ’bout Stephen Wolfram? Yup, mathematics guy, wrote some software to do advanced math real quick. Well, he’s starting a new online website, and here’s what it does… You type in your question, and it’s got a big encyclopedia of a bunch of info, right? So it figures out your question… and sends you the answer. Don’t think that math ain’t at the bottom of it. The website’s up later this month… called Wolfram Alpha. so check it out, the next cool thing, brought to y’all by MATH.

Math ain’t too hard. Jus’ take it step by step, once you get the basics down, you get there. How ’bout a practice question to get the juices goin’? Here it is…

Annie is an interior designer, and she’s got a budget of $345 to buy fabric for drapes. She needs 12 yards of fabric. The fabric that she really wants, Fabric A, costs $29 per yard. Her second choice, Fabric B, costs $27.50 per yard, and her third choice, Fabric C, costs $26 per yard. She wants to buy her top choice that she can afford and stay in budget. Which fabric should she buy?

1) Fabric A

2) Fabric B

3) Fabric C

4) All the fabrics are too expensive.

So… what’d'ya get? And how’d ya go about it? Here’s what I figure… I could multiply the cost of each fabric by 12 yards to find out how much each would cost, but that seems like too much work to me. So I wanna take the shortest short-cut I got. Here’s what I did… take the total budget, $345, and divide it by 12 yards of fabric. That gonna give me the budget PER YARD, then I can jus’ compare that with all the prices.  $345 divided by 12 is $28.75, so I got my max price per yard. Now, I can’t afford the $29 fabric, jus barely. Don’t know bout you, but I’d be all smooth-talkin’ the fabric store owner to try to get a discount. But dat ain’ t part of the question. So the answer’s 2, Answer B, the $27.50 fabric.

And, you notice, this GED question’s all ’bout a real-life job that’d really use this kinda math. So, keep it in mind… math’s real good for your future!

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GED Math Word Problem Advice http://www.passged.com/student_blogs/curtis/2009/01/26/ged-math-word-problem-advice/ http://www.passged.com/student_blogs/curtis/2009/01/26/ged-math-word-problem-advice/#comments Mon, 26 Jan 2009 18:05:15 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=88 Yo, guyz an’ gals. Connie wrote in askin’ for advice about word problems:

I’m not bad in math except when it comes to word problems any advice?

Hey, the GED’s real big on word problems, so you gotta get the hang of them. Why’d they gotta have word problems? Cuz they ain’t so much int’rested if you can figure out 3x + 4 = 12 as if you can figure out how much you’ll save each month if you buy generic soda instead of regular soda. See what I mean? One’s a plain math problem, the other’s a word problem. You’ve gotta first figure out what math you need to use it! See, my math teacher told me, math’s like a tool box. You got all these different math tools, and they help you do different things. You gotta know when to use what tool, to solve the problem you got in front of you. So, a math word problem is like a real-life problem that you might use math to solve. Okay, okay, whatcha really wanna know is, how to solve ‘em?

1) Read the Problem and Figure Out What It’s Asking

The first step is to figure out what the answer you’re lookin’ for is. How ’bout that question I asked before?

Greg buys 4 2-liter bottles of brand-name soda a week, at the price of $1.29 per bottle. One week each month, the soda goes on sale for $.79 per bottle. The store also has generic soda, which always costs $.99 per bottle. How much will Greg save in one year by buying the generic soda instead of brand-name soda?

There’s a word problem for ya’. So, read it through. What’s the main idea? What’s it asking? What is it you’re trying to find? In this place the answer is savings, in one year, of buying generic soda. It can help you out to rewrite what you’re trying to find in your own words:

Find the savings, in one year, of buying generic soda.

2) Look at What Information You’ve Got

Go through the problem and make notes of what information it gives you. This is what you’ve got to work with. I might go through the problem an’ pick out:

2-Liter Sodas Bought: 4 bottles a week
Costs: $1.29 each, $.79 once a month for 1 week
Generic Costs: $.99 each

Sometimes it helps to draw a picture or a chart. Anything that helps you get the info straight in your head.

3) Make a Plan

Now you gotta figure out what to do. How do you take the info it gives you, an’ get from there to the answer? This is where thinkin’ it through comes in. You need a plan. You got all the tools in your math toolbox: addition, subtraction, multiplication, division. Which ones make sense? What info do you need to use?

Well. Let’s look at it, one step at a time. We wanna know how much he’ll save in a year. So, how much does he spend in a year? Let’s start there. Then, we’ll figure out how much he’ll spend if he buys generic. Then, we want to know the difference of the two. That means, subtracting. So, that’s my plan:

1) Figure out how much Greg spends in a year.
2) Figure out how much Greg would spend buying generic.
3) Subtract to find out how much he’d save.

3) Do the Math!

Step 1: How much does he spend in a year? Greg buys 4 sodas a week. Most of the time, they’re $1.29 each. To figure out how much he spends most weeks, what do you do? Multiply, right? $1.29 times 4 sodas:

4 × 1.29 =5.16

Okay, that’s a regular week. What about when the soda’s on sale? That’s:

4 × .79 =3.16

Now, you need some more thinking. How many weeks in a year does he spend $3.16? Once a month, right? So that’s 12. For each of 12 weeks, he pays $3.16. Multiplication again:

3.16 × 12 =37.92

Now, that’s part of the year. The rest of the year, he pays 5.16. Now, to know how many weeks that is, you (1) need to know there’s 52 weeks in a year, and (2) need to subtract, because you want to know how many are left.

52 – 12 = 40

So, for 40 weeks, he spends $5.16:

40 × 5.16 =206.40

Great. Long road to get here. But what’s the total he spends in a year? When you want to know a total, you want to add…

206.40 + 37.92 = 244.32

Yikes! That’s a lot of dough. (Hey, most GED problems won’t have so many steps, but it’s good practice.)

Step 2: How much would he spend buying generic? This is easier, cuz it’s all one price. $.99 times 4 bottles times 52 weeks.

.99 × 4 × 52 = $205.92

Step 3: Subtract to find out how much he’d save:

$244.32 – 205.92 = $38.40

4) Does the Answer Make Sense?

Okay. Take a step back. Does what you did make sense? Does it seem like a reasonable answer to the question? The question is, how much will he save in a year if he buys generic soda, about .30 cents less (usually) than brand-name soda–but sometimes .20 cents more. So, on average, what’s he saving? .20 per soda? Maybe? 50 weeks, 4 sodas a week, so 200 sodas-ish a year, at 20 cents would be about 40 bucks.  The answer’s about 40 bucks. That sounds reasonable. I ain’t bein’ exact enough to estimate an answer, but I know my answer at least ain’t way off in the wild somewhere. I mean, if I got $384.00 by accident, I’d KNOW it was wrong.

The other advice I got is, practice! Here’s some places to get practice word problems. Hey, they won’t all be this complex. Start with the easier ones an’ work yo’ way up. An’ show me any of ‘em that give you problems. I’ll try walkin’ thru ‘em.

http://www.mathplayground.com/wordproblems.html

http://www.quia.com/pop/13193.html

http://www.quia.com/jq/19998.html

http://www.cdli.ca/CITE/math_problems.htm

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com.

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GED Math Word Problems… http://www.passged.com/student_blogs/curtis/2009/01/22/ged-math-word-problems/ http://www.passged.com/student_blogs/curtis/2009/01/22/ged-math-word-problems/#comments Thu, 22 Jan 2009 18:45:03 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=83 Hey, yo. Here’s a question by Tanya that Liz forwarded me from her blog:

Im about to take my math test,I am horrible in math.right now I am working on word probloms.How do I know if these word probloms are asking me to subtract,divide,multiply or add.please help.

Yeah! Tough, ain’t it? But the GED wants to know if you can do math on the fly, you know. That’s why they give you word problems. Like, you’re waitin’ in the line at the supermarket. Do you got enough money for what’s in your cart? How do you know? You’ve got to choose what math to do to figure it out… in this case, ADD together everything in your cart, and SUBTRACT from how much money you’ve got.

Try to think through the problem in concrete terms. Picture it. How do the diff’rent numbers relate to each other?

ADD if you need to find a total, figure out what more than one thing together is. For example, if you deposit $40, $160 and $30 in your bank, and you started out with $200, how much you got? You ADD because you’re trying to find out what it is all together.  $200 + $40 + $160 + $30 = $430. That’s more than I got!

SUBTRACT if you need to find the difference between two things or what you got left over, or how much bigger one thing is than another. For example, how much more will you save from buying the $150 TV instead of the $180 TV? Subtract, because you need to find out how much more one is than the other. $180 – $150 = $30 saved by buyin’ the cheaper TV.

MULTIPLY if you need to find out the total of something repeated over a number of years, over a number of miles. For example, if you’re going to drive 40 miles to the beach, and each mile costs $0.10 in gas, how much will the drive cost in gas? You need 10 cents for each mile… and that’s what MULTIPLICATION is for. All you gotta do is multiply 40 x $0.10 to get $4.00 in gas for the whole trip.

DIVIDE if you need to find out a part of something, or how something separates into even amount. So, if Karen paid $45 for 5 of the same scarf to give to people for Christmas, how much is one scarf? It’s 45 ÷ 5 = $9 for each scarf. DIVIDING divides a number into equal parts.

That’s the quick low-down. Here’s some resources for more info on word problems…

http://mathforum.org/dr.math/faq/faq.word.problems.html

http://academic.cuesta.edu/acasupp/as/706.htm

http://www.studygs.net/mathproblems.htm

And get some practice…

http://www.satmathpro.com/SMP_WordProblems.html

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com.

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GED Math: Word Problem http://www.passged.com/student_blogs/curtis/2009/01/22/ged-math-word-problem-2/ http://www.passged.com/student_blogs/curtis/2009/01/22/ged-math-word-problem-2/#comments Thu, 22 Jan 2009 18:19:29 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=81 Yo, all. Here’s another word problem from Zaher…

Satix is at a flea market. She wants to get the most knives at the lowest price. But she also wants to get at least one of each. The prices of the knives are: $ 4.30, $12.80, $11.50, $7.30, $ 7.50. If she has $50 to spend how much will her change be?

This is a tough word problem, so you gotta think it through. Hey, it’s great practice. Cuz if you can think through this, thinkin’ through some other word problems’ll be E-Z. This is what I call a number sense problem, cuz there ain’t no real advanced math, just makin’ sense of it, bein’ logical about it, and doin’ some basic math.

So, Satix wants one each of all the knives. You know she’s gonna buy one of each, so she’s going to buy at least:

$ 4.30 + $12.80 + $11.50 + $7.30 + $ 7.50 = $43.40

She’s spent $43.40, just on one of each knife. But she wants as many knives as possible. So, does she buy anything else? How much’s she got left?

$50.00 – $43.40 = $6.60

She’s got $6.60 left, so she can buy one more of the cheapest knives.

$6.60 – $4.30 = $2.30

That gives her $2.30 in change. Not enough to get another knife. So she be done. And you got the answer to the question…how much change she got left? $2.30. There ya go.

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com.

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GED Math: Adding and Subtracting Fractions http://www.passged.com/student_blogs/curtis/2008/12/22/ged-math-adding-and-subtracting-fractions/ http://www.passged.com/student_blogs/curtis/2008/12/22/ged-math-adding-and-subtracting-fractions/#comments Mon, 22 Dec 2008 16:39:33 +0000 Curtis http://www.passged.com/student_blogs/curtis/?p=70 Hey, all. Michael’s studyin’ for his GED, an he sent me this question:

am having problem with Lesson-7 page 491 on A. on Add or subtract as Directed reduce to the lowest terms.Am trying to figure out the form to work the fractions. am stuck on this one. Michael

Okay, here’s the rule with adding and subtracting fractions. Let’s start with a problem:

5/12 + 2/5

For starters, make sure you got the same number on the bottom of both fractions (the same denominator). If the denominators are different (like 12 and 5), how do you get them the same?

Well, you can change the number on the bottom of a fraction by multiplying or dividing BOTH the number at the top (numerator) and the number at the bottom (denominator) by the same number. So, what’s a number you can multiply 12 and 5 into evenly? Gotta go all the way up to 60 to do it. I figure it out by seeing what the multiples of 12 are, until I find one that 5 goes into (cuz I know 5 will go into it if it ends in 5 or 0). Hey, practice those times tables!

So, since 12 x 5 is 60, you change the denominator of the first fraction to 60 by multiplying the top and bottom by 5:

5/12 = (5 x 5) / (12 x 5) = 25/60

For the second fraction, you gotta multiply by 12:

2/5 = (2 x 12) / (5 x 12) = 24/60

So, the problem gets to be:

25/60 + 24/60 =

Now, it’s easy. Just add the top numbers, and the bottom number stays the same:

25/60 + 24/60 = 49/60

Now, you want to REDUCE. That means, is there anything you can divide evenly into the top and bottom? No, there isn’t. So the answer is 49/60. Let’s try a subtraction problem… they’re similar. Make the bottom numbers the same, and then subtract the top numbers. But let’s mix it up with mixed numbers.

5-1/4 – 3-2/3 =

Okay, there are a couple of ways to do this, but I find the easiest is to make them into improper fractions first. How many 4ths is 5? It’s 20/4 (4 x 5 = 20). So, 5-1/4 = 21/4… you can do the same thing with 3-2/3. Three is the same as 9/3 (or 3 x 3 thirds), so 3-2/3 = 11/3 (9 thirds plus 2 thirds is 11 thirds). Now, it’s just fractions:

21/4 – 11/3 =

So, how do we make 4 and 3 the same? What do they both go into? 12.

21/4 = (21 x 3) / (4 x 3) = 63/12

11/3 = (11 x 4) / (3 x 4) = 44/12

To figure out the problem, just subtract the top numbers, and leave the bottom one the same:

63/12 – 44/12 = (63 – 44)/12 = 19/12

Now, what’s 19/12? Take 12/12 out to make 1, and you’ve got 7/12 left: 1-7/12.

Okay, we didn’t really reduce on any of these, so let’s do one that needs to reduce.

11/36 + 7/36 =

The bottom numbers are already the same, so just add the top numbers and leave the bottom number the same:

11/36 + 7/36 = (11 + 7)/36 = 18/36

Okay, now we got 18/36. It needs to be reduced. How do I know? Well, first they’re both even numbers, so I know for sure that 2 goes into both. (If they both ended in either 0 or 5, I’d know 5 went into both… seriously, check your times tables.)

Since 2 goes into both, I can divide both by 2:

18/36 = (18 ÷ 2) / (36 ÷ 2) = 9/18

Now, I can see pretty clear that 9 goes into 18:

9/18 = (9 ÷ 9) / (18 ÷ 9) = 1/2

So, 18/36 is 1/2. If I saw right away that 36 was twice 18, I wouldn’t'a had to divide twice… that’s why it helps your GED to get really good at the basic math, dividing, multiplyin’, just workin’ with numbers.

Let me know if this helps studyin’ for your GED! And let me know if you got any more questions abou adding and subtracting fractions.

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com.

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