A new December and a new bunch of puzzles from mscroggs.co.uk.

I don’t quite know how to get to this logically, so I wrote a program. k = 756.

28 = 2²*7

756 = 108*7 = 2²*3³*7

28*756/(28+756) =

2²*7*2²*3³*7/(4*7+108*7) =

2⁴*3³*7²/(112*7) =

2⁴*3³*7²/(2⁴*7²) =

3³, integer