← Methods
Multiply by 11
Eleven of something is ten of it plus one more of it. Shift it up to ten times, then add the original back.
When it works
Anything times 11.
Worked through
34 × 11 = 374
- 34 × 10 = 340Ten times anything is a shift, so start there.
- 340 + 34 = 374Eleven of them is ten of them plus one more.
10 problems, every one of them this method.