# Math Problem “Crossing the river?”

• On the weekend, friends of mine went camping. They were camping on a small island in the middle of the lake. There were eight adults and two children in all.
• When they went to cross the lake and return home their boat was missing. They searched and searched but all they could find was an old canoe. It wasn’t as big as the boat and they were worried it wouldn’t carry them all. So, they tested it and found the boat could carry either:
• • One or two children
• At first they thought some of them would be stranded forever, but finally, they figured out how to get them all safely across the lake.
• Can you figure it out?
• —————
• Repeat the problem using counters. I want to know the number of crossings it takes to shift the 8 adults and 2 children.
• —————
• What if one of the adults was sick and didn’t end up going camping? How would that change the number of crossing?
• —————
• Let’s adjust the number of adults. How does the number of crossings change when the number of adults changes? Record all your data. Can you find an algebraic pattern?