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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