When can I use this method?
For multiplying numbers near 100. The numbers can be either more than 100 or less than 100 or a combination of the two.
You may also use this method to multiply numbers a little farther away from 100 as long as their differences from 100 are easy to multiply.
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Download Practice sheet for MULTIPLYING NUMBERS NEAR 100
- This method uses the concept (100 + a) (100 + b) = [(100 + a) + b] + ab or [(100 + b) + a] + ab, where ‘(100 + a)’ and ‘(100 + b)’ are numbers near 100 and ‘a’ and ‘b’ are the respective differences.
- Whenever the number is more than 100, the difference is written as positive (+ve).
- Whenever the number is less than 100, the difference is written as negative (-ve).
- When both numbers are either less or more than 100, you add the product of differences.
- When one number is more than 100 and another less than 100, you subtract the product of differences.
Related Shortcuts –