Well, the last digit in the product will only come from the last digits of the numbers that you're multiplying together. So for 0.303 & 4.48, that last digits are 3 & 8 so that last digit in the product would come from So 4. There are only two options that end in 4, 1.35744 & 0.13574. You can by the magnitude of the numbers that it isn't as small as 0.13574 so the answer must be 1.35744.
5/12=10/24 and 7/8= 21/24, add those and you will get 31/24 subtract 31 from24 and get 7 your new fraction is 1 7/24 that is 5/12 + 7/8 in simplest form