Long Multiplication

Long Multiplication is a special method for multiplying larger numbers.

It is a way to multiply numbers larger than 10 that only needs your knowledge of the ten times Multiplication Table.

Let us say we want to multiply

612 × 24 But we can do better!
 * First we multiply 612 × 4 (=2.448),
 * then we multiply 612 × 20 (=12.240),
 * and last we add them together (2.448 + 12.240 = 14.688).

When we multiply 612 × 20 we only need to multiply 612 × 2 and place the result one column over (so it is the same as multiplying by 20).

We just have to be careful about lining up the columns. Here is how to do it (press the play button):

More Than Two Digits
The same idea works when multiplying by more than two digit numbers. We just have to move over more spaces: