Multiplication is, by definition, the addition of some number so many amount of times. Therefore, to multiply a number by a desired number requires the same principle.

To multiply:

1. Display the original number.
2. Think of desired multiplier.
3. If multiplier has more than one digit, multiply by digits separately
4. Add the original number however many times desired.
5. Move to the next digit and repeat step 4 if multiplier has more than digit.

Example: (4×5)

4=4
0000-|-0
-0000|-0

4+4=4×2=8
0000-|-0
0-000|0-

8+4=4×3=12
000-0|-0
00-00|-0

12+4=4×4=16
000-0|-0
000-0|0-

16+4=4×5=20
00-00|-0
0000-|-0

Here is another example with one number having two digits: (5×2.5)

5=5
0000-|-0   (0)
0000-|0-   (5)
0000-|-0• (.0)

5×2=10
000-0|-0
0000-|-0
0000-|-0•

5×0.5=2.5
0000-|-0
00-00|-0
0000-|0-•

10+2.5=12.5=5×2.5
000-0|-0
00-00|-0
0000-|0-•

External links

• Multiplication on a Japanese abacus selected from Abacus: Mystery of the Bead