Multiply 6 by 10 and then by 100. Instead of repeated addition, notice the shortcut: multiplying by 10 appends one zero, and multiplying by 100 appends two zeros.

Example

mult-6-by-10-100.math
6 x 10
6 x 100

step: 6 x 10: append 0 -> 60
step: 6 x 100: append 00 -> 600
multiply-by-powers-of-ten Multiplying a whole number by 10 shifts every digit one place to the left, which is the same as writing a 0 at the end. Multiplying by 100 shifts two places, writing 00 at the end.