Chinese Line Multiplication | The Line Trick That Beats Long Multiplication Every Time

Multiply 23 × 12 in about ten seconds, with no calculator and nothing past the ten times table. Draw two groups of lines, count where they cross, and read the answer right to left. The first time you see it, it looks like a party trick. Then you notice the crossings land exactly where place value says they should, and it becomes a shortcut you can trust. This video draws it, counts it, checks it against the area model and the standard algorithm, and shows where it stops being worth the trouble. Chapters 0:00 A ten-second trick 0:15 The problem: 23 × 12 0:22 One line for every digit 0:51 Count the crossings 1:16 Read it right to left 1:45 Why it works 3:10 The catch: carrying 4:03 Where the method breaks down 4:40 One more tool, then your turn By the end you can do 23 × 12, 23 × 14 with a carry, and 31 × 12 without writing a column. It's the kind of arithmetic that buys back minutes on the SAT, ACT and ASVAB, where the clock is the real opponent. New speed-math video every Saturday. #math #mathtricks #SAT #ACT #ASVAB #mentalmath #multiplication