19 is only 1 away from 20, so you prefer to start by multiplying 20 times 5, which equals 100. Then we need to take away a squadron of 5, because there are actually only 19 squadrons, not 20. 100 take ...

Is There a Way to Square 2-Digit Numbers Quickly? While it’s easy to calculate the squares of single-digit numbers like 5 in your head (since those squares are part of the basic multiplication table ...

Methods similar to this go back thousands of years, at least to the ancient Sumerians and Egyptians. Around 1956, the famous Soviet mathematician Andrey Kolmogorov conjectured that this is the best ...

You can solve a lot of multiplication calculations by working things out in your head. Knowing your times table facts is a great way to multiply smaller numbers in your head. However, there are also ...

This summer, battle lines were drawn over a simple math problem: 8 ÷ 2(2 + 2) = ? If you divide 8 by 2 first, you get 16, but if you multiply 2 by (2 + 2) first, you get 1. So, which answer is right?

To multiply two numbers with the same unit places, such as 97 and 98, one can write it as (100-3) x (100-2). Next, add the two numbers 3 and 2 together, which gives 5. Subtract 5 from 100 (as it falls ...

THIS AIN'T YOUR FATHER'S MATH: Here's a bit of low-tech edtech that might just relieve some of the anxiety around multiplying double and triple digit numbers. The Magical Maths blog reports that the ...

A concrete method for multiplication. When your child first learns to multiply two two-digit numbers, she will use the area model. This visual tool illustrates how to decompose numbers and find four ...