Stage 6 · Big numbers & speed
Two-digit × 11
Split the digits, put their sum between.
How to do it
Method
Split the digits, put their sum between
35 × 11: 3 + 5 = 8 → 385
Another way
Column multiplication
35 × 11 = 350 + 35 = 385
In full
Split the digits and drop their sum in the middle. 35 × 11 → 3 _ 5 with 3+5=8 → 385. If the middle hits ten, carry: 78 × 11 → 7 _ 8, middle 15 → 8 _ 5 _ 8 → 858. You can also multiply in columns (35 × 11 → 350 + 35 = 385) — the same answer.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
31 × 11
Show the answer and working
Answer: 31 × 11 = 341
31 × 11: split 3 and 1, put 3 + 1 = 4 in between → 341
Example 2
15 × 11
Show the answer and working
Answer: 15 × 11 = 165
15 × 11: split 1 and 5, put 1 + 5 = 6 in between → 165
Example 3
28 × 11
Show the answer and working
Answer: 28 × 11 = 308
28 × 11: split 2 and 8, the middle is 2 + 8 = 10, which carries: 2 + 1 = 3, 0 in the middle → 308
Example 4
91 × 11
Show the answer and working
Answer: 91 × 11 = 1001
91 × 11: split 9 and 1, the middle is 9 + 1 = 10, which carries: 9 + 1 = 10, 0 in the middle → 1001
Practise two-digit × 11 in the game →Stage 6 · Big numbers & speed · Free to start, unlimited questions, no download