Math Word Problems Demystified - A Self Teaching Guide

Try These

Write each in symbols:

1. Six times a numberxdecreased by four.


2. A numberxincreased by six.


3. Eight less than a numberx.


4. Fifteen minus one-third of a numberx.


5. The square of a numberxplus 7.

SOLUTIONS:

1. 6x
   4


2. xþ 6


3. x
   8


4. 15
   ^13 xor 15
   x 3


5. x^2 þ 7

In the previous examples, only one unknown was used. At other times, it is

necessary to represent tworelatedunknowns by using one variable. Consider

these examples:

‘‘The sum of two numbers is 12.’’ When you are given two numbers whose

sum is 12 and one number is, say, 7, how would you find the other number?

You would say 12
7. So if one number isx, the other number would be

12 
x.

‘‘One number is six more than another number.’’ If I told you one number is

10, how would you find the other number? You would add 10þ6. So if one

stated number isx, the other number would bexþ6.

‘‘One number is five times another number.’’ If I told you one number is

two, how would you find the other number? You would multiply two by five.

So if one number isx, the other number would be 5x.

‘‘One number is twelve less than another number.’’ If I told you one number

was 30, how would you find the other number? You would subtract 30
12.

So if one number isx, the other number isx
12.

Try These

Represent each using symbols:

1. The sum of two numbers is 15.

84 LESSON 8 Algebraic Representation