Well, 6/8 can be simplified: divide the numerator and denominator by 2, then your simplified fraction is 3/4. Now, multiply straight across: 4 times what=12? 3 does. So, you do the same thing to the numerator, because whatever you do to the denominator must be done to the numerator, and same reversed. 3*3=9, so the answer to this is 9/12!!
Tim spends 1/3 each weekday sleeping and 7/24 in school. We can write 1/3 as 8/24 so we have a common denominator. Now we can see that Tim sleeps for 1/24 time of a weekday more then he spends in school.
