Sometimes when I am out with friends and family, a medium sized multiplication problem comes about. For some reason, I can do these types of problems in my head fast. I’m not sure where I learned this trick, but I am going to share it with you.
Third Grade Math
I remember back in third grade when we used to play multiplication games. We would compete with other students in the class to see who could learn the basic multiplication tables first. We started with the 2’s (2 x 2 all the way to 2 x 9) and then moved onto the 3’s, 4’s, all the way to the 9’s. The tip that I am going to show you assumes that you already know this basic math.
Multiples of Ten
The process that I use for multiplication involves breaking the problem down into two parts. The first part is a multiple of 10 and the other is the basic math explained above. Let’s look at an example:
17 x 6 =
When faced with a problem like this, I first break down the larger number in my head as a multiple of 10. So, I take 10 out of the 17 and it leaves me with 10 x 6. You can do that in your head and get 60. I then take the remainder of 7 and multiply it by 6. That is a problem from the basic section and it gives me 42. All you need to do then is add the 60 and the 42 and it gives 102. Isn’t that a lot easier to do in your head? Here’s another example just to be sure you got it:
16 x 8 =
First, break the larger number down into a multiple of 10. That will give you 10 x 8 which equals 80. Then take the remainder of 6 and multiply it by the 8. That gives you 48. Add the 80 and the 48 and you get your answer of 128.
What do you think? Easy? Will it be useful to you?