How to use it
- Pick the even factor to halve.
- Double the other factor.
- Repeat until the multiplication becomes easy.
See it in action
16 × 35 → 8 × 70 → 4 × 140 = 560.
How to verify it
Compare with 10×35 + 6×35 = 350 + 210 = 560.
Common mistake
This works for multiplication, not addition.