When adding fractions without a common denominator, it is necessary to find a common denominator before adding the numerators. Find two equivalent fractions by determining the least common multiple of the two denominators and using that as the denominator for both fractions.
Long Division. There are different methods for dividing multi-digit numbers (long division). One way is a combination of estimation/ trial and error and multiplication. There is also a commonly used algorithmic method that is well explained and illustrated here at mathisfun.com.