Numbers ending with 5

Now we relate the formula to the ‘squaring of numbers ending in 5’.

Consider the example 25²

Here the number is 25. We have to find out the square of the number. For the
number 25, the last digit is 5 and the 'previous' digit is 2. Hence, 'one more than
the previous one', that is, 2+1=3. The Sutra, in this context, gives the procedure
'to multiply the previous digit 2 by one more than itself, that is, by 3'. It becomes
the L.H.S (left hand side) of the result, that is, 2 X 3 = 6. The R.H.S (right hand
side) of the result is 52, that is, 25.

35²= 3 X (3+1) /25 = 3 X 4/ 25 = 1225;

65²= 6 X 7 / 25 = 4225;

105²= 10 X 11/25 = 11025;