Math · Stage 2
List every way by cases
Fix one thing at a time, then list the rest in order — casework catches every arrangement and choice, and never misses one.
✦ Math📘 Stage 2 · S2⏱ ~10 min🧒 Ages 6–7★ Free to start
I can list arrangements and choices systematically by casework.
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Kavi's Case Boxes 📦
Kavi wants every 2-letter code from the cards A, B, C 🔤 — and worries, "If I jump about, I'll miss one!" So Kavi makes three boxes: A-first, B-first, C-first. "Now I fill one box at a time: A → AB, AC … B → BA, BC … C → CA, CB. Two in each box — 2 + 2 + 2 = 6 ways!"
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What your child will learn
1Put each way in its caseTo list every 2-letter code from the cards A, B, C, make a case for each possible first letter. Then sort every code into the right box — a code goes by the letter it starts with.
2Inside a case, go in orderPick the A-first case. The first letter is fixed as A, so now the second card just counts up in order: B, then C. That gives AB, then AC — two ways, none missed.
3Add the cases upNow count by adding the cases. Each of the 3 cases held the same number of codes: 2 each. Here are two cases joined: 2 + 2 = 4, and with the third case it becomes 6.
4Count the finished listOnce the cases are filled, the last job is easy: count every way. For the three cards there are 6 codes — hop once per code and land on 6.
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A peek inside
List every 2-letter code from the cards A, B, C (no letter twice), by cases. How many ways?
A-first: AB, AC · B-first: BA, BC · C-first: CA, CB → 2 + 2 + 2
Try this at home: Finish the A-first case — 2-letter codes from A, B, C: AB, __
Part of Math · Stage 2 · S2 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.