The two square numbers that add up to 225 are 144+81 = 225
92
The two square numbers which add up to 13 are 9 (which is equal to 3 squared), and 4 (which is equal to 2 squared).
Square numbers.
9 and 36
16 and 9
40
9 + 25
16, 25
the two numbers in the circles add up to the number in the square box!
9 + 16 = 25
55