Forming a Unit Ratio
Kate and Christopher extend their use of diagrams to form a unit ratio in a speed context.
Kate and Christopher compare two different ways of reasoning – multiplicative reasoning and additive reasoning.
Christopher and Kate figure out how many miles a car should travel in one minute so it goes the same speed as a car traveling 10 miles in 4 minutes. This results in a unit ratio.
Kate and Christopher use diagrams to demonstrate why additive reasoning does not work to find a unit ratio.