Easy Multiplication of numbers around 100
Multiplication of two numbers around 100 is even easier than you could ever imagine.
Suppose you want to multiply any two numbers, lets take 95 and 97 for example.
Step 1: We'll find out the difference of the two numbers (95 & 97) from 100.
95 is 5 less than 100 [100-95=5],
97 is 3 less than 100 [100-97=3].
Step 2: Subtract the total difference from 100. Here the total difference will be 8 [Since 5 + 3 = 8]
So after subtracting , we get 92 [ 100 - 8 = 92 ]. This becomes first part of our answer.
Step 3: We multiply the two difference amount i.e. 5 & 3 to get 15 as the second part of our answer.
If you still didn't get it , here's another example for you.
Suppose you mulitiply 88 & 96.
Step 1: Difference of the two numbers ( 88 & 96 ) from 100 are 12 and 4 respectively.
Step 2: Subtracting the total difference of 16 [100- (12 + 40)] from 100 we get 84. [100 - 16 = 84]. So 84 becomes the first part of our answer.
Step 3: Now, we multiply the two difference amount of 12 & 4 to get 48 as second part of our final answer.
So the final answer becomes 8448 .
Self-Exercises:-
a) 92 x 93 =
b) 94 x 98 =
c) 88 x 85 =
d) 87 x 99 =
Answers: a) 8556 (b) 9212 (c) 7480 (d) 8613 .
You might also like: Easy way to multiply with 5 ..
6 comments:
Any suggestion or comment is welcomed from my part.
Nice suggestion! Thanks for sharing.
I really like when people are expressing their opinion and thought. So I like the way you are writing
It is useful to try everything in practise anyway and I like that here it's always possible to find something new. :)
what if the second part is a three digit number?
In the self exercise question three 15X12=180. then what should we do?
easy to solve but any method to make easy the second part that is to be muliplied. if so pl reply at tiwari.siddhi@gmail.com
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