Maths Fun » Multiply up to 20x20 in Your Head
Would you believe that in five minutes you can learn the secret to multiplying any two numbers from 11 to 19 in your head without using a calculator? Well it’s possible – provided you know basic multiplication tables plus addition and subtraction. There’s a great trick to this and once you learn the steps for these calculations, your grades will improve, you will amaze your friends, and your parents will be very proud of how great you are doing in math. Once you learn the trick by using the “map of Africa” method, you’ll be on your way to be able to multiply up to 20x20 in your head. The 20x20 multiplication table lesson is very easy to follow and guaranteed to work every single time. So get ready to stop using the calculator for these really easy 20x20 multiplication table calculations and do them in your head – it’s much faster!
Think that multiplying digits up to 20 by 20 is hard? It is not! Here you can learn how to do it in under five minutes. With these tips, you will be able to multiply any number from 11 to 19 without needing a calculator.
Here’s an example.
» Say you need to multiply 15 by 13.
» When computing, make sure that the larger number is at the top of your equation.
» Draw a mental picture of the African shape – it should cover the number 5 and the number 3 from 13.
» Add 15 to 3 – the answer will be 18.
» Multiply it by 10 to get the answer 180.
» Multiply the covered number (in this case, 3) with the digit above it (number 5). The answer will be 15.
» Add 180 and 15 to get 195 (the answer to the equation 15 x 13.)