Xiao Fang = Xiaohong -8

Xiao Ming = Xiao Fang× 3

From the above three formulas: Xiaohong+12 = small square× 3 = (Xiaohong -8)×3.

So Xiaohong is folded: (8× 3+12) ÷ (3-1) =18.

Xiao Ming got a discount: 18+ 12=30.

Cube discount: 18-8= 10.