Explanation:
this applies to any two consecutive square numbers
1 and 4
144 and 169
since a square number is formed by multiply a number by itself and the normal sequence of numbers is odd even odd even...
no odd number will be followed by its kind and same to even numbers
square of 2 - square of 1
4 - 1 = 3
square of 13 - square of 12
169 - 144 = 25