Pseudocode

1. num := number to multiply by 11
2. sum := sum of first and second digits of num
3. if sum < 9:
4.	insert sum between first and second digits of num
5. else:
6.	insert second digit of sum between first and second digits of num
7.	add 1 to first digit of num

Examples

  • 42 * 11:
    1. sum = 4 + 2 = 6
    2. product = 462
  • 99 * 11:
    1. sum = 9 + 9 = 18
    2. product = 1089