Double and Half Trick: Make 125 × 48 Easy | Multiplication Trick for Kids (Grades 3–6)

Learn the double and half trick: turn a hard multiplication into an easy one without changing the answer. The rule: double one number and halve the other. Repeat until the problem is easy. Example: 45 × 16. Double 45 to 90, halve 16 to 8. 90 × 8 = 720. It works because × 2 and ÷ 2 cancel out. Best when one number ends in 5 and the other is even: 14 × 35 → 7 × 70 = 490. Keep going for bigger numbers: 125 × 48 → 250 × 24 → 500 × 12 → 1000 × 6 = 6000. This is the last trick in Foundations 1. All ten are in the playlist below. Chapters 0:00 35 × 18 in one sneaky move 0:19 The rule 0:27 Example: 45 × 16 (and why it works) 0:51 Your turn: 25 × 28 1:15 When to use it 1:23 14 × 35 1:39 Boss level: 125 × 48 2:00 Your challenge: 45 × 22 2:09 Foundations 1: complete Practice (answers in the pinned comment) 45 × 22 75 × 16 35 × 14 18 × 25 12 × 45 Previous trick: Multiply by 111 → [video 9 link] All 10 tricks in order → [playlist link] Math Sigmas is a weekly mental math channel for kids in grades 2–6, and for anyone training for Math League, Number Sense or MOEMS. New trick every week. #mentalmath #mathtricks #multiplication #mathforkids