Math Word Problems Demystified - A Self Teaching Guide

6. In a three-digit number, the hundred’s digit is twice the ten’s digit
   and the one’s digit is 3 less than the hundred’s digit. If the sum of the
   digits of the number is 7, find the number.


7. The sum of the digits of a two-digit number on a stock car is 16.
   The ten’s digit is two more than the one’s digit. Find the number.


8. In a two-digit number, the one’s digit is three more than the ten’s
   digit. If the digits are reversed, the new number is one less than three
   times the original number. Find the number.


9. In a three-digit number, the ten’s digit and the one’s digit are the
   same and the hundred’s digit is three less than the ten’s digit. If the
   sum of the digits is 9, find the number.


10. In a two-digit number, the one’s digit is five less than the ten’s digit. If
    the number is equal to 8 times the sum of its digits, find the number.

SOLUTIONS:

1. Letx¼the one’s digit andxþ 8 ¼the ten’s digit; then

xþ 8 þx¼ 10

2 xþ 8 ¼ 10

2 xþ 8 
 8 ¼ 10 
 8

2 x¼ 2

x¼1 (one’s digit)

xþ 8 ¼9 (ten’s digit)

The number is 91.

2. Letx¼the one’s digit and 3x¼the ten’s digit; then
   3 xþx¼ 8

4 x¼ 8

41 x

41

¼

8

4

102 LESSON 10 Solving Digit Problems