If you liked the Fun Fact Multiplication by 11, you’ll enjoy seeing how to take that idea one step farther. Here’s...

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For the term "mental arithmetic".

## Squaring Quickly

You may have seen the Fun Fact on squares ending in 5; Here’s a trick that can help you square ANY...

Continue reading...## Squaring Numbers between 40 and 60

Here’s a quick way to square numbers between 40 and 60. You know the squares of 40, 50, and 60,...

Continue reading...## Multiplying Complementary Pairs

Quick! What’s 23 x 27? 621 There’s a trick to doing this quickly. Can you see a pattern in these...

Continue reading...## Squares Ending in 5

Give me any 2 digit number that ends in 5, and I’ll square it in my head! 452 = 2025 852 = 7225, etc....

Continue reading...## Difference of Squares

You have all learned that a2 – b2 = (a + b)(a – b) But perhaps you haven’t thought about how to...

Continue reading...## Multiplication by 11

Multiplication by 11 is easy! To multiply by a 2-digit number add the two digits and place the sum in...

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