Blue +20
Red +25
Green +30
Purple +35

I haven’t seen any better idea for this question so far

since there are 3 circles drawn, the question likely to be asking the student to suggest 3 operations that may be performed consecutively on the inputs to obtain the outputs.

since the input numbers have interval of 1 and the output numbers of have interval of 6, one of the operation could be multiply by 6, or some multiple of 6.

minimum need 2 operations. multiply by 6, followed by add 10. since the question wants 3 operations, we add one more operation.

can have many possible answers, examples ...
(1) subtract 1, multiply by 6, add 16.
(2) multiply by 12, add 20, divide by 2.
(3) add 5, multiply by 6, subtract 20.
etc, etc.

That would actually be difficult for a Sec 1 to manoeuvre around though considering the possibilities