Math Word Problems Demystified - A Self Teaching Guide

x¼2 (one’s digit)

3 x¼ 3  2 ¼6 (ten’s digit)

The number is 62.

3. Letx¼the ten’s digit and 9
   x¼the one’s digit; then
   original number is 10xþ(9
   x); reversed digits number is 10(9
   x)þx

10 xþð 9 
xÞþ 27 ¼ 10 ð 9 
xÞþx

10 xþ 9 
xþ 27 ¼ 90 
 10 xþx

9 xþ 36 ¼ 90 
 9 x

9 xþ 9 xþ 36 ¼ 90 
 9 xþ 9 x

18 xþ 36 ¼ 90

18 xþ 36 
 36 ¼ 90 
 36

18 x¼ 54

181 x

181

¼

54

18

x¼3 (ten’s digit)

9 
x¼ 9 
 3 ¼6 (one’s digit)

The number is 36.

4. Letx¼the ten’s digit andxþ 1 ¼the one’s digit; then
   original number is 10xþ(xþ1); reversed digits number is 10(xþ1)þx

2 ð 10 xþxþ 1 Þ
 3 ¼ 10 ðxþ 1 Þþx

2 ð 11 xþ 1 Þ
 3 ¼ 10 xþ 10 þx

22 xþ 2 
 3 ¼ 11 xþ 10

22 x
 1 ¼ 11 xþ 10

LESSON 10 Solving Digit Problems 103