Math Word Problems Demystified - A Self Teaching Guide

STRATEGY: Letx¼the smaller number and xþ 8 ¼the larger number.
Since the problem asked for the sum, write the equation asxþxþ 8 ¼26.

IMPLEMENTATION: Solve the equation forx:

xþxþ 8 ¼ 26

2 xþ 8 ¼ 26

2 xþ 8 
 8 ¼ 26 
 8

2 x¼ 18

21 x

21

¼

18

2

x¼ 9

Hence one number is 9 and the other number isxþ8or9þ 8 ¼17.

EVALUATION: Check the answer: 9þ 17 ¼ 26

EXAMPLE:If eight plus three times a number is equal to 23, find the
number.

SOLUTION:

GOAL: You are being asked to find one number.

STRATEGY: Letx¼the number. Eight plus three times a number is written
as 8þ 3 xand the equation is 8þ 3 x¼23.

IMPLEMENTATION: Solve the equation.

8 þ 3 x¼ 23

8 
 8 þ 3 x¼ 23 
 8

3 x¼ 15

31 x

31

¼

15

3

x¼ 5

LESSON 9 Solving Number Problems 89