3rd Grade Counting Sides and Vertices Worksheet: 8 Flat Shapes

Every flat shape is built from straight sides that meet at corners, and math calls those corners vertices. This 3rd grade counting sides and vertices worksheet starts with a short reminder box. It shows a rectangle with one vertex and one side labelled, so the two words are clear before the counting begins. Below it, there are eight flat shapes in colour, such as an arrowhead, a cross, a triangle, an octagon and a tall rectangle. The last three are trickier, because they look like an hourglass, a house with cut corners and a letter M. Under each shape, your child writes the number of vertices and the number of sides. The page sits on light grid paper, so the lines are easy to follow. Page two is the answer key, with every number filled in.

Sixteen numbers to check

The answers are 4 and 4 for the arrowhead, 12 and 12 for the cross, and 3 and 3 for the triangle. Then come 8 and 8 for the octagon, 4 and 4 for the rectangle, and 6 and 6 for the hourglass. The house with cut corners has 6 and 6, and the letter M has 5 and 5. All sixteen numbers in the key are right.

The page has two small slips. It writes "i.e," instead of "i.e." on both pages. The question also says "does the following shapes have," which should be "do." This is grade 2 content, so the page works well as a quick review.

At the table: counting sides and vertices with a dot

Give your child a pencil and ask them to put a small dot on every vertex before they count. Then they count the dots, and they trace each side with a finger while they say the numbers aloud. Because each side is touched once, no side is missed or counted twice.

After three shapes, ask a question: what do you notice about the two numbers? In every closed shape on this page, they are the same. As a result, your child can check each answer by counting both ways.

After the page: a shape hunt at home

Walk around the house and look for flat faces, such as a book cover, a window, a tile or a slice of cheese. For each one, your child names the shape and counts its vertices and sides out loud. Next, draw a new shape together and try to beat the cross, which has twelve sides. This game keeps the words "side" and "vertex" fresh long after the page is done.