If "4/2/7" is all we have to work with, then PEMDAS rules will save the day. Do the division from left to right.
4/2 becomes 2. Then we have 2/7, a proper fraction. I don't see where an improper fraction would come from in this case.
Do you mean what does infinity + infinity equals to? If so, infinity + infinity = infinity.
1 3/5 cans of tomatoes are used in each quart of the sauce
