Answer :

OOHHH!! I like sci not! Okay, so you take the decimal ( which in this case is at the end: 68000. ) and move it over as many times as needed until it gets in between the, in this case, 6 and 8. ( 6.8000 ). You need to show exactly how many times it was actually moved so you multiply that number time 10^ whatever place. In this question, it'll be to the 4th place because you move the decimal over 4 times. The answer will be 6.80 x 10^4 OR -written in short hand- 6.8x10E4 
68000 = 6.8 * 10000 = 6.8 * 10^4