Multiplying a 2-digit number by 2 1/5

1. Select a 2-digit number.
2. Multiply the number by 11. Add the digits right to left.
3. Divide the product by 5.

   Example:

1. The 2-digit number chosen to multiply by 2 1/5 is 43.
2. Multiply by 11: the last digit of the product is 3. 3 + 4 = 7 (next left digit). The product is 473.
3. Divide the product by 5: 473/5 = 94.6.
4. So 43 x 2 1/5 = 94.6.

   See the pattern?

1. The 2-digit number chosen to multiply by 2 1/5 is 78.
2. Multiply by 11: the last digit of the product is 8. 8 + 7 = 15. The next digit is 5, carry 1. 7 + 1 = 8. The product is 858.
3. Divide the product by 5: 858/5 = 171.6.
4. So 78 x 2 1/5 = 171.6.