Math · Stage 2
Everyone grows older by the same amount
One birthday for the whole family — everybody adds the very same year, so who is older than whom never changes.
✦ Math📘 Stage 2 · S2⏱ ~10 min🧒 Ages 6–7★ Free to start
I can reason that everyone grows older by the same amount each year (a constant difference), so age gaps are preserved.
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Kavi's Family Birthday 🎂
At the big family party everyone has a birthday on the same day! Kavi is 8, Papa is 34, baby Tam is 2. "When the candles are blown, every single one of us adds 1 year," hoots Kavi. Next year: 9, 35, 3. Nobody jumps ahead, nobody falls behind — because everyone grew by the same amount. So the gap between any two of them stays exactly the same, forever.
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What your child will learn
1Older age = younger age + the gapKavi is 8 and Tam is 2. The older age is the younger age plus the gap between them. The bond shows it: 2 (Tam) + 6 (the gap) = 8 (Kavi). Slide to explore the two parts.
2One birthday — everyone adds the same yearAt the party BOTH people add the same 1 year. Kavi: 8 → 9. Tam: 2 → 3. Tap each card and check the gap between them.
3The gap is the jump on the linePut two ages on a number line and count the jumps from the younger age up to the older one — that jump is the gap. Slide BOTH ages along by the same number of years: the jump between them never gets any longer or shorter.
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A peek inside
Kavi is 8 and baby Tam is 2. How much older is Kavi? Will that change after everyone's next birthday?
gap now = 8 − 2 = 6 · next year both +1: 9 and 3 → 9 − 3 = 6
Try this at home: Kavi is 8, Tam is 2. How much older is Kavi? Will the gap change after everyone's next birthday?
Part of Math · Stage 2 · S2 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.