Curtis’s Speed GED » GED Math

GED Math: Taking a Closer Look

Curtis — Tue, 10 Nov 2009 02:14:43 +0000

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?

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

GED Math: Percentage Decrease

Curtis — Thu, 04 Jun 2009 18:30:52 +0000

Hey, yo, all. How’s the GED math goin’ on? Last time, I talked about problems with percent increase, and now let’s look at percent decrease. It be all about knowin’ what the question’s really askin’. Remember, I said, when it asks what’s the percent increase, what it means is:

What Percent OF the Original amount IS the Difference between the two amounts?

P × O = D

Percent decrease is pretty much the same thing. What percent of the original amount is the difference between the two amounts? Only difference in figuring it out is that the second amount is lower than the first, not higer. No sweat. The percent times the original amount still equals the difference. It’s just a decrease, not an increase. Get it?

Let’s look at it. Here’s a practice problem.

I filled up my car, so it had 15 gallons of gas in the tank. So, I drove out to my uncle’s house and back, and it took $18 in gas at $2 per gallon to fill up the tank. What was the percentage decrease in gas during the trip?

Did I get you with a tough one? More than jus’ one step here. Try to figure it out, then I’ll walk you through it…

Okay, here’s the deal. You need to do some steps to get the info you need to solve the problem… so what info do you need? Well, here’ s the formula we said….

P × O = D

Percent decrease (P) is what you’re tryin’ to find. Original value, you know that, it was 15 gallons, like the problem said.

P × 15 = D

But what’s the difference between the old amount of gas an’ the new one? Well, you gotta figure it out. It’s the amount of gas that got used, right? The info you have is that it took $18 at $2 per gallon to fill up the tank. How much gas can you get at $2 a gallon for 18 bucks? You know that, right? Divide 18 by 2, an’ you got 9 gallons. It took 9 gallons to fill up the tank, so the gas left at the end of the trip was 6 gallons. The difference between the 15 gallons started with an’ the 6 gallons ended with is 9 gallons. Get it?

P × 15 = 9

So, the percentage decrease is 9 divided by 15, or .6

P = 9 ÷ 15 = .6

Now, you gotta turn .6 into a percentage, an’ you jus’ move the decimal point over two to the right. So’s it’s 60%.

P = 9 ÷ 15 = .6 = 60%

The guy used 60% of his gas on the trip.

Knowin’ what a percent increase or decrease problem is askin’ is the big thing, and bein’ able to think through word problems. Let me know if you got any GED math that’s givin’ you a problem, an’ I’ll help you out.

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

GED Math: Percent Increase

Curtis — Thu, 28 May 2009 17:59:03 +0000

Percents! Yo, I know most everyone out there hates percents. I got a kinda question lots of people say’s confusin’. That’s when it’s askin’ about percent increase. This one’s in lotsa word problems. An’ I know how you love word problems! How ’bout we try one out?

I got a new hard drive, to back up my computer. The old hard drive I was usin’ was 250 GB. Now, the new one’s 640 GB. Sweet! So, what’s the percent increase in hard drive space from the old hard drive to the new one?

Give it a minute, try to work it out. What’dya think?

Here’s how I’d work through this one. First, you got to know what they mean when they say “what’s the percent increase?” It means, what PERCENT of the ORIGINAL AMOUNT is the DIFFERENCE BETWEEN (increase between) the two amounts. That’s puttin’ it in some context, right? First off, you got 3 important numbers. (1) PERCENT (P) = what you’re trying to find. (2) ORIGINAL (O) AMOUNT. (3) DIFFERENCE (D) BETWEEN old and new amounts.

Now, in math, “of” usually means “times.” And “is” usually means “equals.” So, I could put it like this.

P × O = D

What Percent OF the Original amount IS the Difference between the two amounts?

Well, you know the original amount. Dat’s my original hard drive size, 250 GB.

P × 250 = D

And to find the “difference” between two things, you gotta subtract. So the difference is the two amounts subtracted: 640 − 250 = 390

P × 250 = 390

To find P, the percent, you got to get P all by itself. So, to get rid of the “times 250,” you divide both sides by 250…

P × 250 ÷ 250 = 390 ÷ 250

P × 1 = 390 ÷ 250

P = 390 ÷ 250

P = 1.56

Now, P’s supposed to be a percent. To change a number to a percent, move the decimal place two to the right… the answer is:

156%

Let’s check it out… 100% bigger would mean it’s 250 GB bigger… one whole hard drive bigger. And it’s more than that. It’s more like 1-1/2 times bigger… that’s 150%. So the answer makes sense, right? Now, can you do the same thing with a percent decrease problem? What if it asked what the percent decrease was from 640 GB to 250 GB? Think about it, I’ll have a percent decrease problem in my next post….

Get that GED quick… you can do it!

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

What Can GED Math Do for You?

Curtis — Wed, 13 May 2009 17:39:51 +0000

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!

GED Practice Problem: Distance, Rate, an’ Time!

Curtis — Thu, 12 Mar 2009 01:24:38 +0000

Yo, all you GED-studiers. Workin’ hard? Hammond wrote in with a practice question… good one for thinkin’ through distance an’ speed problems. So, I thought I’d put it in a post, not jus’ comments…. Here goes:

Two cyclists start biking from a trail’s start 3 hours apart. The second cyclist travels at 10 miles per hur ans start 3 hours after the first cyclist who is traveing at 6 miles per hour. How much time will pass before the second cyclist catches up with the first from the time the second cyclist started biking

Okay. bicyclists. start 3 hours apart. You want to know when they meet, so you want to know when the distance is the same.

distance = rate × time

So, bicyclist 1, let’s call him “A” … “A” = 6 mph × time
An’ bicyclist 2, let’s call him “B” … “B” = 10 mph × (time – 3)

The minus 3 is cuz he’s travelin’ 3 hours less than the other one. Now, because “A” = “B” (they’ve gone the same distance when they meet), you’ve got an equation your can solve:

6 × time = 10 × (time – 3) …
that’s the same as: 6t = 10(t – 3)

Now, it’s jus’ algebra, right? you multiply the 10 by both the “t” and the 3…

6t = 10t – 30

Now, subtract 10t from both sides to get the “t”s all together… remember, cuz it’s minus 30, your 30’s gonna be negative:

6t – 10t = -30
-4t = -30

Now, divide by -4 to get t all by itself… a negative divided by a negative is a positive, which is good, otherwise they’d be time travelin’ into the past! Keep it real, man!

t = -30/-4 = 7.5 hours

Now, in what I wrote, “t” is the time of the first cyclist. t – 3, or 4.5 hours is the time from when the second cyclist starts to when he catches up. I ain’t too sure, the way the question’s worded, which time it wants. Read the original again an’ see if you can figure it out… is it from when the first guy starts or from when the second guy starts?

Now, the time seems pretty reasonable, but…. let’s check. First cyclist goes for 7.5 hours at 6 mph, that’s 45 miles. Second cyclist goes for 4.5 hours at 10 mph, that’s 45 miles, too. There’s your answer. It’s 7.5 hours from when the first guy started, and 4.5 hours from when the second guy started. There ya go.

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

GED Math: Casio Calculator

Curtis — Thu, 12 Mar 2009 01:16:10 +0000

Hey, all. Qweenbe wrote in askin’ about the calculator for the GED test… and I’d been meanin’ to do a post about it.

See, it’s a scientific calculator with all kindsa cool functions that you don’t need on the test. It’s important to know how to use it so you don’t hit the wrong order of buttons and get the wrong answer. And the better you gonna get with the calculator, the faster you can do the math.

Hey, these things only cost bout 10 or 15 bucks. So, go get yo’self one, first off, to practice at home. Here’s a link to buy it on Amazon: Casio fx-260 Solar Calculator

Case ya don’t got one, here’s what it looks like:

So, here’s the most important stuff:

Press “on” to turn it on. Yeah, I know, basic, right? It’ll say “DEG” in the top of the screen. Don’t worry what it means, if it says “DEG,” you’re in the right mode to do regular math. But if it says somethin’ else, press “mode” and “4″ to get it to say “DEG”. Now you set!

Jus’ always press “ON” or “AC” to start a new problem, so you know your memory’s clear. Havin’ the last number from the last problem in memory’s gonna mess you up.

To do basic math, jus’ put in the math problem like it’s written “5 + 8 × 16″ or “29 × (4 + 200)”, or whatever, and press the equal key at the end to get the answer. Remember: you got to press the equal key to get the answer!!!

It knows the order of operations, that is, like, what to do first in the problem. So, it’ll do (1) things in parenthesis, then (2) multiplication an’ division, then (3) addition and subtraction. So, if you’re fixin’ up 9your own equation to punch in, remember–that’s the order it’s done in. You type in parenthesis along with all the rest of your problem. Them’s the [(--- and ---)] keys, for the open and close parenthesis.

Now for the things that are different than just typin’ in the problem:

To get a square root, type in whatever you want the square root of, then “shift” (top left) then the key with x² on it, then equal to get the answer. To get a number squared, just type in the number and then press the x²key and equal.

To make a number negative, press the “+/-” key AFTER the number. So, to type in -9, type “9″ “+/-”

That’s the basics! Now, here’s some links to learn more:

http://www.ilc.org/cfmx/GED/GED_sample_m2.cfm?Menu_ID_Sel=35200&Lang_Sel=1
http://www.ket.org/GED2002/Mathcalc/Mathcalc1.htm

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

GED Practice Word Problem

Curtis — Wed, 18 Feb 2009 20:59:19 +0000

Hey all. Zaher wrote in with this practice problem while back, and I thought it’d make a good post, so here it is:

A room is 24 feet long, 18 feet wide, and 9 feet high. How many square yards of wallpaper are needed to paper the four walls of the room?

You got your basic area problem, right? How do I know it’s “area”? Well, area is the space on the surface of something. Like, how much carpet covers a floor, or how many tiles on a bathroom wall. Or paint on a room. If you’re covering a surface, you’re talkin’ area. Now, how to solve it?

You got a few bumps in the road. First, you got dimensions in feet, anâ€™ you want an answer in yards. Whenever you got different measurements in a problem, I recommend always changinâ€™ everything to the dimensions you want in yoâ€™ answer first off. That means, changinâ€™ all the feet to yards. Now, thereâ€™s three feet in a yard, and datâ€™s jusâ€™ somethinâ€™ you got to know. So, to change feet into yards, divide by 3.

24 feet = 8 yards
18 feet = 6 yards
9 feet = 3 yards

Hey, you gotta know youâ€™re on the right track when all the numbers divide out evenly! Too bad real life donâ€™t work dat way. â€˜k. Soâ€™s, now itâ€™s important to picture what the questionâ€™s about, specially with this kinda dimension question. You got a room, 8 yards by 6 yards, and 3 yards tall.

Whatâ€™s the area of the 4 walls? Thatâ€™s the real questionâ€¦ a wallpaper or carpet or tile (or anything that goes on a flat surface) question is an area question.

Soâ€¦ each wall got the same height, the height of the roomâ€¦3 yards (9 feet):

wall 1: 3 yards Ã— ?
wall 2: 3 yards Ã— ?
wall 3: 3 yards Ã— ?
wall 4: 3 yards Ã— ?

So, whatâ€™s the width of the walls? well, 2 walls is 8 yards long (the two walls opposite of each other on the sides of the room thatâ€™re 24 feet) and 2 walls is 6 yards long (the two walls opposite of each other on the sides of the room thatâ€™re 18 feet).

wall 1: 3 yards Ã— 8 yards
wall 2: 3 yards Ã— 8 yards
wall 3: 3 yards Ã— 6 yards
wall 4: 3 yards Ã— 6 yards

To find the area, multiply:

wall 1: 3 yardsÂ Ã— 8 yards = 24 square yards
wall 2: 3 yardsÂ Ã— 8 yards = 24 square yards
wall 3: 3 yardsÂ Ã— 6 yards = 18 square yards
wall 4: 3 yardsÂ Ã— 6 yards = 18 square yards

And to find the total, add:

24 + 24 + 18 + 18 = 48 + 36 = 84 square yards

Answerâ€™s 84!

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

What to Study for GED Algebra

Curtis — Wed, 18 Feb 2009 20:35:37 +0000

Hey, all. Someone wrote in askin’ about studyin’ for GED algebra, and I replied in the comment. But I thought, this is good stuff for everyone to know, so here it is… what you gotta know ’bout GED algebra:

Hey there! Algebraâ€™s got a lot of stuff in it, and it takes a while to learn. You can look at a lot of the algebra articles here: http://www.passged.com/student_blogs/curtis/category/algebra/. Hereâ€™s the absolute, need-to-knowâ€™s:

1) Gotta understand the idea of a variable. A variable is a letter or symbol that stands for something unknown or something that can change. A lot of the time, youâ€™ll see â€œxâ€ used as a variable: x + 5 = 10 â€¦ why do you use a variable? Cuz you want to figure something out, and to put the â€œsomething you donâ€™t knowâ€ into a math equation you need some sort of symbol for it. Thatâ€™s where the x comes in. Youâ€™ll need to be able to understand what 2x means (2 times x) and mutliply, add, and subtract with variables to move them around.

2) Gotta understand how to move numbers around in an equation. In an equation, you can add the same number to both sides, subtract the same number from both sides, multiply both sides by the same number, or divide both sides by the same number (as long as itâ€™s not zero). Why do you want to do that? So you can move all the numbers to one side, and the variable to the other, and figure out what the variable equals. So, for x + 5 = 10, you can subtract 5 from each side. Then, x = 5. Easy.

3) Gotta be able to see what an equation means in real life. So, take a word problem and make an equation out of it.

4) Understand inequalities, like 4 < 2x or x +5 > 10.

5) Gotta know how to deal with negative numbers and fractions. Why? These are the main things thatâ€™ll mess you up in moving around numbers. Better you understand them, the better youâ€™ll do.

6) Helps to know about exponents, like x². You wonâ€™t get into real high exponents, jusâ€™ understand what â€œsquaredâ€ means (something times itself) and what a square root means.

7) Helps to know about graphing a lineâ€¦ like whatâ€™s a slope? How do you get a line on a graph from an equation?
The hardest part is quadratic equations (you can see my article â€™bout them). But thereâ€™s not gonna be a lot about them on the GED, so no big sweat.

Datâ€™s the basics. I know itâ€™s a lot, anâ€™ I canâ€™t promise my website covers it all. But your son can always write in to me with special problems if heâ€™s havinâ€™ trouble with something. Itâ€™s hard to study on your own, so I totally recommend the GED Academy study program at http://www.passGED.com. Itâ€™s got a real complete math course, and if he has a problem he can call up an instructor for help.

GED Math: Fraction Rap

Curtis — Thu, 29 Jan 2009 01:53:56 +0000

Saw this video today. This guy’s got it goin’ on.

http://www.teachertube.com/view_video.php?viewkey=ebd7c1e1b7118af88edc&page=1&viewtype=&category=

GED Math Word Problem Advice

Curtis — Mon, 26 Jan 2009 18:05:15 +0000

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 Ã— 1.29 =5.16

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

4 Ã— .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 Ã— 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 Ã— 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 Ã— 4 Ã— 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.Â 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.