GED Math Word Problem Advice

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.