Clothing drive math

Our class is been tasked with organizing the clothes for the clothing drive. So far this means that we've been in charge of telling the weight has it's coming in. Now we are preparing the clothing for pick up by the diabetes foundation.  This means making sure that the clothes are organized in 20 pound bags for the diabetes people to tally as they put them on their truck. Each student weighs themself, picks up some of the donated clothing and does the math to calculate how much more or less clothing is needed, and then they add it to the pile.  

There is a lot of math going on.