How to calculate square of a number ending in 5
This technique will work for all numbers which end in 5.
Funda – If we remove the last digit ‘5’ from our number and are left with x, then the square will be [Product of x and x+1]25.
#Suppose we want to calculate 65^2.
ð We remove 5 from our number, we are left with 6.
ð Product of 6 and 7 is 42
ð The square of 65 is 4225
#Suppose we want to calculate 195^2
ð We remove 5 from our number, we are left with 19
ð Product of 19 and 20 is 380
ð The square of 195 is 38025
How to calculate square of a number ending in 1,9 or 4,6
This technique will work for all numbers which end at a distance of 1 unit from a multiple of 5.
Funda – Calculate the square of the nearest multiple of 5. Add or subtract (Num + Multiple of 5) from it.
#Suppose we want to calculate 61^2.
ð The square of 60 is 3600
ð The square of 61 will be 3600 + (60+61) = 3721
#Suppose we want to calculate 179^2
ð The square of 180 is 32400
ð The square of 179 is 32400 – (179+180) = 32041
#Suppose we want to calculate 66^2.
ð The square of 65 is 4225
ð The square of 66 will be 4225 + (65+66) = 4356
#Suppose we want to calculate 194^2
ð The square of 195 is 38025
ð The square of 194 is 38025 – (194+195) = 36736
I will continue with other methods of calculating squares in my next post.
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