Math Word Problems Demystified - A Self Teaching Guide

6. Letx¼the number; then

2 x
 6 ¼ 20

2 x
 6 þ 6 ¼ 20 þ 6

2 x¼ 26

21 x

21

¼

26

2

x¼ 13

7. Letx¼the number of calculators in the first box andxþ 4 ¼the
   number of calculators in the second box; then

xþxþ 4 ¼ 40

2 xþ 4 ¼ 40

2 xþ 4 
 4 ¼ 40 
 4

2 x¼ 36

21 x

21

¼

36

2

x¼ 18

xþ 4 ¼ 18 þ 4 ¼ 22

8. Letx¼first integer;xþ 1 ¼second integer;xþ 2 ¼third integer; then

xþxþ 1 þxþ 2 ¼ 39

3 xþ 3 ¼ 39

3 xþ 3 
 3 ¼ 39 
 3

3 x¼ 36

31 x

31

¼

36

3

x¼ 12

xþ 1 ¼ 13

xþ 2 ¼ 14

96 LESSON 9 Solving Number Problems