PLEASE READ THE SHORTCUTS IN ADDITIONS FIRST. SO THAT IT WILL BE EASY FOR YOU TO UNDERSTAND SUBTRACTION SHORTCUTS
SUBTRACTION BY NUMBERS CLOSE TO 100, 200, 300, 400, ETC.
250 - 96
= 250 - (100 - 4) (here, instead of subtracting 96 from 250, we are just subtracting 100 from 250 and then adding 4)
= 250 - 100 + 4 (Why adding? because the actual amount we have to subtract from 250 is 96. but we are subtracting 100. That means, we are subtracting 4 numbers more than we actually deserve. so our 250 will feel bad. so we should add that 4 to it:)
= 250 - 200 + 4 (here also same. In order to subtract 196, we subtract 200 and adding 4)
Note : We can use this logic for any number. According to our convenience.
Subtraction of decimals
= 250 - 100 + 4 (Why adding? because the actual amount we have to subtract from 250 is 96. but we are subtracting 100. That means, we are subtracting 4 numbers more than we actually deserve. so our 250 will feel bad. so we should add that 4 to it:)
= 150 + 4
= 154
250 - 196
= 250 - (200 - 4)
= 250 - 200 + 4 (here also same. In order to subtract 196, we subtract 200 and adding 4)= 50 + 4
= 54
Lets see,
216 - 61 (Here i found it difficult to subtract 61 from 216)
= 216 - (100 - 39) (So i just decided to subtract 100 to it and later will subtract the extra 39)
= 216 - 100 + 39 (Hey, see here. How about writing this 39 as 40 -1 ?)
= 116 + (40 - 1) (dont be confused. just practice this method and you will come to know how easy and efficient method it is :)
= 156 - 1
= 155
Subtraction of decimals
47 - 9.9 (How about dividing this 9.9 as 9 + 0.9 ??)
= 47 - (9 + 0.9) we can write this as...
= 47 - 9 - 0.9
= 38 - 0.9
= 37.1
18.3 - 0.8
= 18 + 0.3 - 0.8
= (18 - 0.8) + 0.3
= 17.2 + 0.3
= 17.5
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