You can multiply x 98 x 5

Fast Multiplication - Fast Calculator Crash Course (Part 4)

When, like now, millions of people are struck by football fever, what is supposedly out of the way has little chance of attracting attention. The happier I am to have your attention. Without a lengthy preamble, I would like to introduce you to an extremely beautiful, cool and spectacularly unusual method for quickly multiplying two-digit numbers. It's a visual method and therefore an absolute must-see!

The ancient Chinese invented them, just as they knew paper, letterpress printing and the compass long before the Europeans.

Let's start with 21 x 32.

The tens and units are translated into corresponding numbers of diagonally arranged lines. Chopsticks already did it back then.

The following figure shows this through color coding.


Illustration: Vlad Sasu

Then you just have to count the intersection points of the lines in the color-coded areas. Finished! Faster than a 5-second terrine.

How do you proceed if the number of intersection points in an area is two-digit?

Of course, by carrying forward tens in the obvious way.

Let's take 34 x 53.

The following illustration is pretty self explanatory.


Illustration: Vlad Sasu

So: 34 x 53 = 1802

And now have fun trying it out!

Here are some suggestions:

13 x 14 =

53 x 32 =

44 x 26 =