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Tool · Eleven Move
Killer Move ×11
Multiply by 11 using neighbouring digits. Keep the outside digits, add each neighbouring pair, then resolve carries from right to left.
The Killer Move builds the answer from digits: first digit → sums of neighbouring pairs → last digit. These are place values, not a string to join blindly. If a place reaches 10, resolve the carry to its left. Practise until you can see the sums and carries mentally.
How it works — explained step by step
No carry: 121 × 11
Neighbour sums and outside digits — one box per place
After resolving carries from right to left
- Start with 1. The neighbouring pairs give 1 + 2 = 3 and 2 + 1 = 3. Finish with the last digit, 1.
- The places are 1, 3, 3, 1. No carry is needed: the answer is 1331.
One carry: 78 × 11
Neighbour sums and outside digits — one box per place
After resolving carries from right to left
A small +1 above a box is a carry arriving from the right. Highlighted boxes pass a carry to the left.
- The first digit, neighbour sum and last digit are 7, 15, 8. The 15 belongs to one place; do not join them into 7158.
- Keep the 8 on the right. From 15, write 5 and carry 1 left: 7 + 1 = 8. Answer: 858.
A carry chain: 123456 × 11
Neighbour sums and outside digits — one box per place
After resolving carries from right to left
A small +1 above a box is a carry arriving from the right. Highlighted boxes pass a carry to the left.
- The pairs give 3, 5, 7, 9, 11. With the outside digits, the places are 1, 3, 5, 7, 9, 11, 6.
- Keep the final 6. From 11, write 1 and carry 1 to the 9.
- 9 + 1 = 10: write 0 and carry 1 again. The 7 becomes 8.
- The remaining places stay 1, 3, 5. Read the completed answer from the left: 1358016.
An extra digit at the front: 99 × 11
Neighbour sums and outside digits — one box per place
After resolving carries from right to left
A small +1 above a box is a carry arriving from the right. Highlighted boxes pass a carry to the left.
- The places are 9, 18, 9. Keep the last 9; from 18, write 8 and carry 1 left.
- The first 9 becomes 10. Write 0 in its place and put the remaining 1 in a new place at the front: 1089.
Build the neighbour sums from left to right, then resolve carries from right to left. A sum of 9 can become 10 when a carry arrives. Start with two digits; longer examples follow the same rule. The trainer uses positive whole numbers. Why it works: multiplying by 11 adds the number to a copy shifted one place left; the digit trick performs that addition locally.