The 10 followed by the little superscript number just represents how many decimal places you move to get your final number. So:
3.25 × 10⁴ just means you move the decimal point (between 3 and 2) four times to the right: 32500 (the decimal point would be after the last 0, so technically it's 32500.0, but you don't need to write that).
When the little superscript number is negative, you move the decimal point to the left:
6.04 × 10⁻³ = 0.00604 (make sure to add a zero before the decimal too).
When you write a standard form number, you have to make sure the number is larger than 0 and less than 10, so converting a number like 2,400,000 would be 2.4 × 10⁵, because you're moving the decimal place 5 times to get 2,400,000.
0.00147 is 1.47 × 10⁻³ because once again, you have to move 3 decimal places to the left.
