Calculating Mathematical Multiplication by Drawing

Few days ago, I learnt a way for calculating mathematical multiplication by drawing. The best way to tell about the process is by an example.

If you want to calculate the multiplication of 12 x 31, do the following.
Look at the first digit of the number at the left side of the multiplication formula. In this case, it’s (1), which is the first digit of the 12. Draw skew lines (from the upper left downward to right) count as the number tells. In this case, only one line; like the following:

Draw two skew lines according to the (2), which is the second digit of the 12, like the previous line; like the following:

Now, do the same for the number on the right side of the formula, but in the opposite direction (from top right downward to left), so they cross the previously drawn lines.
The first digit of 31 is (3):

The second digit is (1):

After that, divide the crossed sections into three sections: left, middle, and right; like the following:

Count the line crosses within each section, and write the count number just below each section, at the same order:



So the result of the multiplication of 12 x 31 = 372

Moreover, for the more complex multiplications, where numbers may consist of more than two digits, the following example will explain more clearly:
Multiply 123 x 321















So, the result of the multiplication 123 x 321 = 39483

Isn’t it nice?!