9514 1404 393
Answer:
(a) 6² +3² +1² +1² = 47
(b) 5² +4² +2² +1² +1² = 47
(c) 3³ +4² +2² = 47
Explanation:
It can work reasonably well to start with the largest square less than the target number, repeating that approach for the remaining differences. When more squares than necessary are asked for, then the first square chosen may need to be the square of a number 1 less than the largest possible.
The approach where a cube is required can work the same way.
(a) floor(√47) = 6; floor(√(47 -6^2)) = 3; floor(√(47 -45)) = 1; floor(√(47-46)) = 1
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(b) floor(√47 -1) = 5; floor(√(47-25)) = 4; ...
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(c) floor(∛47) = 3; floor(√(47 -27)) = 4; floor(√(47 -43)) = 2