The Mosaic Menders — Area as Counting Unit Squares (Grade 3)

About this activity

Tessa shows a mosaic — say a 2-by-3 block of 6 tiles — and children find the one made of the same number of unit tiles, which might be a single row of 6 even though it is shaped nothing like the target. It's a free, interactive Grade 3 math activity that runs right in the browser with nothing to install and no account.

The big idea is that area is a count of unit squares, the same no matter the shape. One of the look-alike choices is a bigger-looking shape with the wrong count — a 3-by-3 of 9 tiles next to a 2-by-3 of 6 — so a child cannot pick by which looks largest and has to actually count the squares. Matching across different shapes is exactly what makes area click as a count rather than an impression.

It is aligned to Common Core 3.MD.C.6 — measuring areas by counting unit squares. No timer, no score — just calm, playful practice.

What's inside this activity

• Designed for Grade 3 learners (ages about 8–9)
• Common Core strand: Measurement & Data
• Aligned to Common Core standard 3.MD.C.6

How to play

Look at Tessa's target mosaic and count how many unit tiles it uses.

Tap the other mosaic with the same number of tiles, even if its shape looks different.

Got it wrong? Try again as many times as you like — there is no timer and no score.

What your child practices

• Measure area by counting unit squares
• Match two shapes that have the same area but look different
• Resist judging area by which shape looks biggest
• Compare rectangles, rows, and L-shapes by their tile count

Learning goals

Measure area by counting unit squares — the focus of Common Core 3.MD.C.6

Understand that area stays the same across different shapes with equal tile counts

Build the unit-square foundation for finding area by rows and columns later