Here's have a look at how the 12’s shortcut work?
Let’s take a look.
12 X 7
the first thing is to always multiply the 1 of the twelve by the number we are multiplying
by, in this case 7. So 1 X 7 = 7.
Multiply this 7 by 10 giving 70. (Why? We are working with BASES here. Bases are the
fundamentals to easy calculations for all multiplication tables.
Now multiply the 7 by the 2 of twelve giving 14. Add this to 70 giving 84.
Therefore 7 X 12 = 84
Let’s try another:
17 X 12
Remember, multiply the 17 by the 1 in 12 and multiply by 10
(Just add a zero to the end):
1 X 17 = 17, multiplied by 10 giving 170.
Multiply 17 by 2 giving 34.
Add 34 to 170 giving 204.
So 17 X 12 = 204
lets go one more
24 X 12
Multiply 24 X 1 = 24. Multiply by 10 giving 240.
Multiply 24 by 2 = 48. Add to 240 giving us 288
24 X 12 = 288 (Seems Simple, Isnt ?? They are !!)
4 comments:
what a lol.. anyone who falls for this ought to be declared the Weakest in Maths! ha!
Well said Abi. I assume half of the people are in transition from weak to strong.So bear with their weakness..!
The technique looks simple, yet have never known it. Thanks for sharing such info.
There is no necessity to multiply the 1 of twelve to the number .
This is merely a method known as chunking . whereby
12 = (10 + 2) so
12*7 = (10*7) + (2*7)
you can use the same method to calculate all numbers that are near 10
For example
667*9 = ??
9 = (10 -1)
so
667*9 =(667*10)-(667*1)
= 6670-667
= 6003
67*9 = ??
= 670-67
= 603
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