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 ...

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?

This article reveals a simple and effective shortcut for multiplying numbers that end in 5. Perfect for students, it breaks down the trick for both single-digit and double-digit numbers ending in 5, ...

In this video, I explain how to perform two-digit operations quickly using mental strategies. We'll cover **addition**, ...

People tend to obsess over making computer software faster. You can, of course, just crank up the clock speed and add more processors, but often the most powerful way to make something faster is to ...