which of these numbers can not be obtained by adding less than four perfect squares?

Thanks

Squares (I assume you cannot use the same perfect square more than once)...so which THREE add up to one of the numbers?   (1 4 64   add to 69....there is one!)

1

4

9

16

25

36

49

64

81

There is no rule on using more than one of the same perfect squares.

64 + 25 = 89     is another one

49 + 1 + 9 = 59       Is another ...I'm guessing ALL of them will work out.....

I think that 79 wouldn't not work out.Though i'm not too sure

81 + 9 + 9 = 99

Now.....79 hmmmm   can't see how to get there!  Must be 79