The given number is 6.02 × 10⁹. It is written is scientific notation.
As you see it has two parts:
The first part are the digits with the decimal point after the first digit. This part is called mantissa. The mantissa can only have one digit, between 1 and 9, before the decimal point.
The second part is a power of 10. The exponent can be either positive or negative.
If the exponent is negative means that the decimal point must be moved to the left and if the exponent is positive means that the decimal point must be moved to the right.
In the number 6.02 × 10⁹ the exponent is 9, so you must move the decimal point 9 places to the right:
