Teach the rule of sum and rule of product in a fun, simple way that a 3rd grader can understand. Stress that when we use the rule of sum, we only need 1 step to finish the task, but when we use the rule of product, we need multiple steps to finish the task. You can use tree diagram to help students understand the rule of product better.

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Hi there! Sometimes we need to make choices. Like choosing a snack - we could pick an apple or a banana. Or choosing a toy - we could pick the red one or the blue one. When we have different ways to do things, we need to count all the possibilities! The Rule of Sum is super easy! When we choose ONE thing from different groups, we only need ONE step to finish our task. Like choosing one snack: we can pick from 3 fruits OR 2 cookies. We use the word OR and ADD the numbers together. 3 plus 2 equals 5 ways total! Now let's learn the Rule of Product! This is different because we need MULTIPLE steps to finish our task. Like choosing an outfit - first we pick ONE shirt, AND then we pick ONE pair of pants. We need to complete ALL steps to have a complete outfit. This is different from the Rule of Sum where we only needed one step! Tree diagrams are magical! They help us see all the different paths we can take. Look - we start at the top, then branch out to our shirt choices. From each shirt, we branch out again to our pants choices. Each complete path from start to end represents one complete outfit. Count all the endpoints - that's our total! 2 times 2 equals 4 outfits!