The number is written in scientific notation, where we write a number so that it has single digit to the left of decimal sign and is multiplied by an integer power of 10.
In general notation power of 10 is not used and we multiply the number in single digit by the power of 10 to get it in simple standard decimal notation.
Multiplying by a positive power of 10 means moving decimal to right and in case power is negative (this is when the number is less than 1) it meanss moving decimal to left. This is done by the power of 10.
