The first two digits of a number are the product of the first two digits.

For example, 5×3 equals 15.

The middle two digits of a number are the product of the first number and the third number.

For example, 5×2 equals 10.

The last two digits are the sum of the last two digits. Multiply the first number and subtract the middle number.

For example, (3+2)×5-3 equals 22.

9+9+9 equals 8 18 1 153.