Vedic / Quicker / Shortcut Math ⇒ Topic : Square root a number ending with 5
|Squaring a number ending in 5 is the easiest if you know the trick.|
Number given to you can be a two digit number or three digit number or five or six digit number,
it does'n t matter.
The same trick can be applied to find the square of any number ending in 5.
Let us now discuss the steps to follow
Step 1:Multiply the ten's digit of the given number with its immediate next number.This will be the 1st digit of the answer.
Step 2:Put 25 next to the result of step 1.
Logic behind putting 25 is that the number will always end with 5 and 52 is 25.
You get the answer
Let us find squares of numbers ending in 5 using this trick
Example 1:(35)2=?Step 1: 3 is the ten's digit in the given number 35.
Immediate next number to 3 is 4.
Hence,by multiplying 3 & 4 we get 12(3x4=12).which is the 1st digit of the answer.
Step 2: Now putting 25 next to 12 we get the answer as 1225.
Answer: (35)2= 1225
Now you try to square 25,45,15,55,65,75,85,95 & see how quickly you can square.
Step 1: 12 is the ten's digit in the given number 125.
Immediate next number to 12 is 13.
Hence,by multiplying 12 & 13 we get 156(12x13=156).which is the 1st digit of the answer.
[To multiply a 2digit by 2digit number when ten's digit of both numbers is 1 you can apply a trick to get your answer quickly.
1st digit =1
middle digit =add unit's place digit of both numbers(2+3=5)
unit's place digit=Multiply unit place digit of both numbers(2x3=6)]
Step 2: Now putting 25 next to 156 we get the answer as 15625.
Ans (125)2= 15625
Now you try to square 105,115,135,145,155,165,175,185,195 & see how quickly you can square.
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