Congratulations to Sam in the 3rd grade and Nicky B. and Tessa in the 6th grade for finding that 65 can be expressed as the sum of the squares of both 1 and 8 and also of 4 and 7.
But as Jack F. points out in the 11th grade, 50 is expressible as the sum of the squares of 7 and 1, and also of 5 and 5. Sixty five is the smallest number to fit the bill if we require the squares to be different numbers but fifty is the smallest without that requirement.