Yohaku

Yohaku(TM) is a new type of number puzzle created by Mike Jacobs. It will test your number sense and problem solving skills. Each yohaku is either an additive or a multiplicative puzzle (as indicated by the symbol in the bottom right of the grid). Your task is to fill in the empty cells such that they give the sum or product shown in each row and column. Yohakus are great for use in classrooms as a lesson starter, or for the morning commute, or for something to accompany an afternoon cup of tea. Some yohakus will take a few minutes to solve, others will have you puzzling for longer.