Multiplying Two Numbers Close to but greater than 100
To multiply two numbers close to but greater than 100, use the
following steps:
- Find the difference of each of the numbers from 100.
- Multiply these differences; write as the last two digits
of the answer on the right.
- Add the difference of one number to the other original
number; write as the first two digits of the answer on
the left.
Example:
103 × 102 =
- Find the differences of each number from 100: 103 - 100 =
3; 102 - 100 = 2
- Multiply these differences and write as the last two
digits of the answer. 2 × 3 = 6. Since we need to use
two digits, write 06.
- Add the difference of one number to the other original
number. Either combination will work. 2 + 103 = 105 or
103 + 2 = 105. Write 105 as the first two digits of the
answer.
103 × 102 = 10506.
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