Question

(6+12+18+24+...600)²:(3+6+9+12+...+300):(1+2+3+100)

Answer 1

(6+12+18+24+...600)²:(3+6+9+12+...+300):(1+2+3+100) =
=6²(1+2+3+4+...100)²:3(1+2+3+4+...+100):(1+2+3+100) =
=6²:3:1=36:3=12

Answer 2

$(6+12+18+24+...+600)^2:(3+6+9+12+...+300): \\ :(1+2+3+...+100) \\ (6+12+18+24+...+600)^2=[6(1+2+3+...+100)]^2= \\ =36(1+2+3+...+100)^2= \\ =36(1+2+3+...+100)(1+2+3+...+100) \\ 3+6+9+12+...+300=3(1+2+3+...+100) \\ 36:3=12$