Question

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

  2  A  B

+ A  B  1

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   B  1  8

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Answer 1

The addition of B and 1 is giving 8 i.e., a number whose ones digits is 8. This is possible only when digit B is 7. In that case, the addition of B and 1 will give 8. In the next step,

A + B = 1

Clearly, A is 4.

4 + 7 = 11 and 1 will be a carry for the next step. In the next step,

1 + 2 + A = B

1 + 2 + 4 = 7

Therefore, the addition is as follows

   2 4 7

+ 4  7 1

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   7 1 8

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Hence, the values of A and B are 4 and 7 respectively.