You have 2 containers. One holds 7 units, the other holds 5 units. You need to measure out 8 units. Using the two containers how would you measure 8 units???
I thought maybe counting by two's- fill up the seven unit one, pour that into the 5 unit one and you have 2 units left. Do it 4 times and you get 8 units, but that requires another container. Is there a way to do it with just the two containers???