Math · Stage 5
Recognise square and triangular numbers
Square numbers are dots packed into a square — n × n (1, 4, 9, 16, 25…). Triangular numbers are the running total 1 + 2 + 3 + … (1, 3, 6, 10, 15…). Learn to recognise each family and generate the next one.
✦ Math📘 Stage 5 · S5⏱ ~12 min🧒 Ages 9–10★ Free to start
I can recognise and generate square and triangular numbers.
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Kavi's Dot Patterns 🔵
Kavi lays out acorns 🌰. "One acorn. Now a 2 × 2 square — that's 4. Now 3 × 3 — that's 9. These are square numbers!" he hoots. "And if I stack rows of 1, then 2, then 3, they build a triangle: 1, 1+2 = 3, 1+2+3 = 6 — triangular numbers. Let me learn to spot each family and build the next one by heart."
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What your child will learn
1Square dots vs triangle dotsSome numbers make a perfect square of dots; others stack into a neat triangle. Tap each card to meet the two families.
2Make a square number: n × nTo build the nth square number, multiply n × n (a number times itself). Tap a row.
3Make a triangular number: 1 + 2 + 3 + …To build the nth triangular number, add up 1 + 2 + 3 + … + n. Each new one adds the next counting number. Tap a row.
4Square, triangular, or neither?
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A peek inside
What is the 6th square number?
the 6th square = 6 × 6 (six rows of six dots)
Try this at home: The 3rd square number is __ (3 × 3)
Ready to play and learn?
Start the free interactive lesson, or print the handout for screen-free play.
Part of Math · Stage 5 · S5 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.