Rule of 11
Split the digits and tuck their sum in the middle.
43 × 11 = 473
43 × 11 the long way is two rows: one 43, and ten of them shifted up.
Adding them, the tens column holds 4 + 3 — the digit sum lands in the middle.
Split the digits, tuck the sum between. Sum 10 or more? Carry the 1.
Your turn
Three to try in your head — tap what you get.
61 × 11
38 × 11
80 × 11
All 36 shortcuts: the Magic Tricks library.