One, Hundred, Ten, Thousand
Decimal number system is a positional numeral system employing 10 as the base and requiring 10 different numerals, the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. It also requires a dot (decimal point) to represent decimal fractions.
To expand numbers by powers of 10 where a power of 10 is any of the integer powers of the number ten thus it is ten multiplied by itself a certain number of times that is when the power is a positive integer. so you need to express the number as a number between 1 and 10 times a power of 10.