Divide 243 by 3:
243 / 3 = 81
Subtract the exponents:
8-2 = 6
So you have 81 x 10^6
Now move the decimal point on 81 to have one digit to the left of the decimal point and then add the number of moves to the exponent.
81 becomes 8.1, and you moved the decimal 1 place, so add 1 to the ^6:
Answer is 8.1 x 10^7
