Multiply Any Number by 11 in 2 Seconds | Mental Math Trick for Kids (Grades 3–6)

Learn to multiply any 2-digit number by 11 in your head, in about two seconds. The rule: add the two digits and put the sum in the middle. If the sum is 10 or more, carry. Example: 25 × 11. Add 2 + 5 = 7, so the answer is 2 7 5 → 275. With a carry: 58 × 11. Add 5 + 8 = 13. Write the 3 in the middle and carry the 1 onto the 5 → 638. Chapters 0:00 Meet Siggy 0:10 The 5-second challenge: 38 × 11 0:30 The rule 0:45 Example: 25 × 11 1:12 Your turn: 36 × 11 1:27 What if the digits add to 10 or more? 1:37 The carry: 58 × 11 2:05 Level up: 123 × 11 2:32 Boss level: 486 × 11 3:08 Your challenge: 47 × 11 3:18 What's next Practice (answers in the pinned comment) 47 × 11 45 × 11 63 × 11 27 × 11 81 × 11 Next trick: Multiply by 101 →    • 324 × 101 in Seconds? Multiply Any Number ...   All 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