If a number with units digit 5 i.e., a5 then the square of that number is _____.

If a number has a units digit of 5, i.e., a5, then the square of that number is = a(a + 1)100 + 25

For example, 85²

= 8 (8+1) × 100 + 25 

= (8 × 9) × 100 + 25

= 7200 +25

= 7225