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.
Square a number ending with 5 within seconds
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
Examples to find square of a 2 digit number ending with 5
Example 1:35²=?
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(3 x 4=12).which is the 1st digit of the answer.
Step 2: Now putting 25 next to 12 we get the answer as 1225.
Ans 35²= 1225
Step 1: 2 is the ten’s digit in the given number 25.
Immediate next number to 2 is 3.
Hence,by multiplying 2 & 3 we get 6(2 x 3=6).which is the 1st digit of the answer.
Step 2: Now putting 25 next to 6 we get the answer as 625.
Ans 25²= 625
Step 1: 6 is the ten’s digit in the given number 65.
Immediate next number to 6 is 7.
Hence,by multiplying 6 & 7 we get 42(6 x 7=42).which is the 1st digit of the answer.
Step 2: Now putting 25 next to 42 we get the answer as 4225.
Ans 65²= 4225
Now you try to square 25,45,15,55,65,75,85,95 & see how quickly you can square.
Examples to find square of a 3 digit number ending with 5
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(12 x 13=156).which is the 1st digit of the answer.
[To multiply a 2 digit by 2 digit number when ten’s digit of both numbers is 1 you can apply below trick to get your answer quickly.
middle digit =add unit’s place digit of both numbers(2+3=5)
unit’s place digit=Multiply unit place digit of both numbers(2 x 3=6)]
Step 2: Now putting 25 next to 156 we get the answer as 15625.
Ans 125²= 15625
Step 1: 13 is the ten’s digit in the given number 135.
Immediate next number to 13 is 14.
Hence,by multiplying 13 & 14 we get 182(13 x 14=182).which is the 1st digit of the answer.
Step 2: Now putting 25 next to 182 we get the answer as 18225.
Ans 135²= 18225
Step 1: 14 is the ten’s digit in the given number 145.Immediate next number to 14 is 15.
Hence,by multiplying 14 & 15 we get 210(14 x 15=210).which is the 1st digit of the answer. Apply the below trick to multiply quickly
https://www.yobankexams.com/2014/01/shortcut-to-multiply-any-2-digit-number-by-15.html
Ans 145²= 21025
Also see
Shortcut to square any number from 10 to 19
Shortcut to square any number from 20 to 29
Shortcut to square any number from 30 to 79
Shortcut to multiply 2digit number by 2digit number
25-625
45-2025
55-3025
15-225
65-4225
75-5625
85-7225
95-9025
thanx q.its vry easy..