Stop the Shape Thief

Let your child know that you’ve received a letter from the head of Odd Squad, Ms. O. Explain that the Odd Squad needs help — is your child ready to help crack a math case? Read the letter from Ms. O aloud.

Next, move through the “Training” and “Casework,” then celebrate with a “Case Closed” learning recap at the end.

Explain that in order to crack “The Case of the Common Chris,” your child will need to know a lot of shapes. Start by giving your child a “Shapes Sheet” handout. Describe a shape on the page and ask your child to point to the shape you are describing — does your child know what it’s called?. You can describe each of the three different shapes by talking about the number of sides, their corners and angles, etc.

Now have your child cut out the shape pieces. Remind your child that shapes can be tricky: smaller shapes can work together to compose, or create other shapes. Hold up two triangles and put them together to make a square. Ask: “What shape did I make using these triangles?” (A square.) “See? A square can be composed of two triangles.”

Have your child experiment with putting the shapes together in different ways to see what new shapes can be composed. For some extra help, your child can use the line art drawing as a guide for how shapes may fit together. Point out what your child discovers! For example, that a large square can be composed of one rectangle, one square and two triangles. Don’t miss the line art drawing at the top of the shapes sheet — all the shapes together compose one large rectangle.

Gather and discuss the children’s findings. For example, Look, a rectangle can be composed of a square and two triangles. A large square can be composed of one rectangle, one square and two small triangles. Show them the line art drawing at the top of the shapes sheet and discuss how all the shapes together compose one large rectangle.

Now your child is ready to crack “The Case of the Common Chris.” Say, “Before we trick Common Chris with our shape composition skills, we’ll first need to identify the most common shape in the room. That way we’ll know which shape Common Chris is planning to steal.”

Draw each shape on a sheet of paper (square, rectangle and triangle), then have your child go on a shape hunt around the room. As your child discovers different shapes in everyday objects, make a tick mark within each shape on the paper to keep count. To help your child get started, you might point out that the cover of a book is a rectangle and that a door is a rectangle, too!

Have your child count the tallies. Which is the most common shape in the room? (Most likely, it will be a rectangle)

Say: “Great work, agent! Common Chris will never spot the rectangles in our room now. As part of our training, let’s review what we learned from the case and enter it in the case file so that future agents-in-training can learn from it.”

Ask: “What did we learn about shapes? What does a rectangle/triangle/square look like? What are different ways we can make a rectangle?”

Write down the findings that your child shares in the case file. Afterward, close the file and write CASE CLOSED across the front. Congratulate your child on a case well-solved!