Lesson Guide
Explanation
Some numbers belong together like a family. 3, 4 and 12 are one: 3 fours make 12. Draw them as a triangle — the whole (12) at the top, the two parts (3 and 4) at the bottom. This one little triangle is about to give you FOUR facts for free.
Your Turn
Draw the triangle for the 2 · 5 · 10 family. Check: 10 on top, 2 and 5 below.
Watch Out
The biggest number always sits at the top — it is the whole that the other two build.
Explanation
From the 3 · 4 · 12 triangle you can write FOUR true facts: 3 × 4 = 12 and 4 × 3 = 12 (the parts build the whole), plus 12 ÷ 3 = 4 and 12 ÷ 4 = 3 (the whole splits into parts). Learn one fact, own all four. That's why fact families are the fastest way to master tables AND division together.
Your Turn
Write all four facts for the 2 · 5 · 10 family. Check: 2×5=10, 5×2=10, 10÷2=5, 10÷5=2.
Watch Out
The whole (biggest number) always starts the ÷ facts and ends the × facts. 3 ÷ 12 is not in the family!
Explanation
The triangle solves missing-number puzzles. ▢ × 5 = 30: put your finger over the mystery corner. What's left? 30 and 5 — and whole with a part means DIVIDE: 30 ÷ 5 = 6. The hidden number is 6. Cover-up works every time: hide what you don't know, and the two visible numbers tell you what to do.
Your Turn
Solve with cover-up: ▢ × 4 = 32, and 27 ÷ ▢ = 9. Check: 32 ÷ 4 = 8; and 27 ÷ 9 = 3.
Watch Out
If the mystery is a PART, divide. If the mystery is the WHOLE (top corner), multiply the two parts.
Explanation
Every table fact you've learned is secretly a whole family. 2 · 6 · 12, 3 · 5 · 15, 4 · 8 · 32, 5 · 10 · 50… each triangle holds four facts. If you know twenty multiplication facts, you actually own EIGHTY facts. Fact families are how a little learning becomes a lot of power.
Your Turn
Pick your favourite table fact and write its whole family. For 6 × 5 = 30: 6×5, 5×6, 30÷5=6, 30÷6=5.
Watch Out
Careful with square families like 4 · 4 · 16 — they only make TWO different facts (4×4=16 and 16÷4=4), because the parts are twins.
Explanation
Real questions become easy when you think in families. '24 wheels, 4 per car' — that's the 4 · 6 · 24 family: 6 cars. '▢ ÷ 3 = 8' — the mystery is the whole, so multiply the parts: 3 × 8 = 24. Whenever ×, ÷ or a missing number shows up, sketch the triangle in your head and let the family do the work.
Your Turn
'45 fingers in the room — how many hands?' Think family. Check: 5 · 9 · 45 → 45 ÷ 5 = 9 hands. Now do the quiz and exercises!
Watch Out
Sense-check every family answer by multiplying back: 6 cars × 4 wheels = 24 ✓.
Step 1: Introduction
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