Page 112 - NUMINO Challenge_A1

Type Study Digits That Letters Represent
1 The sum of the two 2-digit numbers is a 3-digit number. Therefore, A represents 1.

2 Write 1 in the blanks and find the digits that B and C represent to complete the
equation.
12
99

111
B 2, C 9

Problem solving

1 When 1 is carried over from the sum of two , becomes . Therefore, is greater than

by 1. When two are added, the ones digit is a . 89
9
Therefore, the numbers that meet the two conditions are 8 and 9.
98

2 When the 2-digit number 4 is added to the 3-digit number 1 , the hundreds digit can

either be 1 or 2. Therefore, the digit that represents can either be 1 or 2.

If is 1, the equation becomes 1

4

111

Therefore, the in the ones place has to represent 7. When you replace the with 7, the
equation becomes 1 7

74
111

No number can be used to replace .

If is 2, the equation becomes 1

4

22 2
The in the ones place represents 8.

When you replace the with 8, the equation becomes 1 8
84

222
1 is carried over from the sum of the digits in the ones column.

The sum of the digits in the tens column is 1 8 12. Therefore, 3.

2, 8, 3

7Answer Key