Using an Abacus/Multiplication

From Wikibooks, open books for an open world
Jump to navigation Jump to search

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 one 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[edit | edit source]