Count the Sides — Kindergarten Geometry

About this activity

A single shape appears and the child counts its straight sides, then taps the number that matches — a triangle with 3 sides, a square with 4, a pentagon with 5, or a hexagon with 6, with number choices drawn from a pool of 3 through 8. It's a free, interactive Kindergarten geometry activity that runs right in the browser on a tablet, phone, or classroom computer, with nothing to install and no sign-up.

The big idea is that a shape is more than its name — it is made of parts you can count. A child cannot win by recognizing 'a triangle'; they have to trace each edge with their eyes and count the sides one at a time. Because the number tiles include near-misses like 5 next to 6, miscounting by one shows up, which nudges careful, finger-on-each-side counting rather than a quick guess.

It is aligned to Common Core K.G.B.4 — analyzing and comparing shapes by describing their parts, such as the number of sides. No timer, no score — just calm, playful practice.

What's inside this activity

• Designed for Grade K learners (ages about 5–6)
• Common Core strand: Geometry
• Aligned to Common Core standard K.G.B.4

How to play

Look at the shape on the board and count its straight sides, one by one.

Tap the number that matches how many sides you counted, then press Check.

Not quite? Try again as many times as you like — there is no timer and no score.

What your child practices

• Count the straight sides of a triangle, square, pentagon, and hexagon
• Connect a shape to a number — how many sides it has, not just its name
• Count carefully one side at a time instead of guessing the total at a glance
• Tell shapes apart by their parts, like five sides versus six

Learning goals

Count the number of sides on common shapes — the focus of Common Core K.G.B.4

Describe a shape by its parts rather than only naming it

Build the careful-counting and shape-analysis habits that later geometry depends on