Question

Find the values of the letters in the following and give reasons for the steps involved.

   1  2  A

+ 6  A  B

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   A  0  9

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Answer 1

The addition of A and B is giving 9 i.e., a number whose ones digits is 9. The sum can be 9 only as the sum of two single digit numbers cannot be 19. Therefore, there will not be any carry in this step.

In the next step, 2 + A = 0

It is possible only when A = 8

2 + 8 = 10 and 1 will be the carry for the next step.

1 + 1 + 6 = A

Clearly, A is 8. We know that the addition of A and B is giving 9. As A is 8, therefore, B is 1.

Therefore, the addition is as follows.

   128

 + 681

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    809

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Hence, the values of A and B are 8 and 1 respectively.