its fun trying to figure out how this works....So give it a try :)
A method of multiplying integers using only addition, doubling, and halving.
Method:
- Take two numbers to be multiplied
- In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last in the same column, until you write a value of 1.
- In the right-hand column repeatedly double the last number and write the result below. stop when you add a result in the same row as where the left hand column shows 1.
- Examine the table produced and discard any row where the value in the left column is even.
- Sum the values in the right-hand column that remain to produce the result of multiplying the original two numbers together
Here's an example...
Multiply: 12 * 13
Left Col Right Col
i) 12 13
ii) 6 26
iii) 3 52
iv) 1 104
add the right col numbers corresponding to the left col numbers that are odd.
so adding numbers in row(iii) + row(iv) -> 52+104=156
and thats exactly what 12*13 is...
Try for different numbers..it really works!!!
Figure out the reasoning behind this...should be fun :)
do let me know if you get it :)
1 comment:
wow! it's really interesting..
wots d reason behind it tho?!?
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