Math · Stage 2
Two Hidden Numbers — Sum & Difference
You know the total and how many more — draw two bars, snip off the extra, share what's left, and both secret numbers appear.
✦ Math📘 Stage 2 · S2⏱ ~10 min🧒 Ages 6–7★ Free to start
I can find two hidden numbers when I know their sum (total) and their difference (how many more), using a bar model.
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Kavi the Number Detective 🔍
Kavi finds a riddle: "Two acorns hide 🌰🌰. Together they make 10. One has 2 more than the other. Which numbers are they?" Kavi draws two bars — a longer one and a shorter one. "If I snip off the extra 2 from the long bar, both bars match! Then I just share what's left equally." Mystery solved: 6 and 4! 🕵️
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What your child will learn
1The two numbers are two parts of the totalThe sum is the whole; the two hidden numbers are its two parts. Here the sum is 10, and the parts are 6 and 4. Tap ◀ less and more ▶ — the two parts always add back to the sum of 10.
2Snip off the extra, then share what's leftDraw two bars. The longer bar is the bigger number; it sticks out past the shorter bar by the difference. Tap each card to hear the step.
3List the splits, pick the right gapEvery way to split the sum 10 into two parts is shown. Only one pair is exactly 2 apart — that is the answer. Scan the table and find the two partners whose difference is 2.
4See the snip and the share on a linePut the sum 10 at the end of the line. Hop back by the difference to land on the leftover, then split that leftover in half — the halfway point is the smaller number.
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A peek inside
Two acorns 🌰 add up to 10. One has 2 more than the other. What are the two numbers?
snip the difference: 10 − 2 = 8 · share: 8 ÷ 2 = 4 (smaller) · 4 + 2 = 6 (bigger)
Try this at home: Two numbers add to 8 and one is 2 more than the other. Find both.
Part of Math · Stage 2 · S2 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.