Lidl has gone all brassy and hipster this week with all sorts of copper, brass and bronze cooking pots and bowls, perfect for your industrial styled classroom! This week it’s getting harder to avoid the c-word but I managed to find some sets of bowls, where my puzzle for this week comes from. Your job is to fill a tank with exactly 20 litres with any of the bowls below. How much is it going to cost you to do this as cheaply as possible. You can fill the bowls as much as you like. Now try it for different volumes.