9 Mental Math Tricks. Math can be terrifying for many people. This list will hopefully improve your general knowledge of mathematical tricks and your speed when you need to do math in your head. So here's 9 super mental math tricks... 1. Multiplying by 9, or 99, or 999 Multiplying by 9 is really multiplying by 10-1. 2. To multiply a number by 11 you add pairs of numbers next to each other, except for the numbers on the edges. 3.
Multiplying by 5 is just multiplying by 10 and then dividing by 2. 4. This trick only works if you’ve memorized or can quickly calculate the squares of numbers. 5. If a number ends in 5 then its square always ends in 25. 6. Let’s say you want to multiply 42 by 48. 7. Let’s say you want to square 58. 8. There are cases when you’re multiplying two numbers together and one of the numbers is even. 9. To multiply a number by 2, 4, 8, 16, 32, or some other power of 2 just keep doubling the product as many times as necessary. See related article: Beauty of Mathematics.
Solve Your Calculus Problems Online.