Math · Stage 2
Number bonds to 100
Partners that make 100 — so you can take away from 100 in your head, no borrowing.
✦ Math📘 Stage 2 · S2⏱ ~9 min🧒 Ages 6–7★ Free to start
use number bonds to 100 (complements) for fast mental subtraction.
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Kavi's 100-Coin Jar 🫙
Kavi's jar holds exactly 100 shiny coins 🪙. A squirrel grabs 63 and asks, "How many are still in the jar?" Kavi doesn't tip them all out to count — "37!" 63 and 37 are partners to 100, says Kavi. "Know the partner, and taking away from 100 is a snap!"
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What your child will learn
1You already know the 10-partnersA number bond is two parts that make one whole. You know the partners to 10 by heart: 6 + 4, 7 + 3, 1 + 9 … Tap ◀ less and more ▶ to see every pair that still makes 10.
2Tens that make 100Each rod is a ten. It takes ten tens to make 100. Tap + on the 10s to build 40 (four rods) — then picture the 6 rods still missing: 40 + 60 = 100.
3The two-digit trickNow a number that is not a tidy ten: 63 — six rods and three ones. To reach 100: the ones climb to ten (3 needs 7), and the tens climb to ninety (60 needs 30). So the partner is 37.
4From 10-partners to 100-partnersHere are all the partners that make 10. Read each row, then add a zero to both numbers and you have a partner to 100: 3 + 7 becomes 30 + 70!
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A peek inside
Kavi's jar has 100 coins 🪙. A squirrel takes 40. How many are left?
40 + ? = 100 → tens-partner of 4 is 6
Try this at home: Tens-partners to 100: 30 + __ = 100 · 80 + __ = 100 · 50 + __ = 100
Part of Math · Stage 2 · S2 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.