To add fractions by hand:
1) Make sure that they have the same denominator. If not, first start by finding a common denominator.
Ex. Let's find the sum of

, which have different denominators. To give them the same denominator, you need to multiply both or one of the fractions by a number over itself (aka 1) to get the same denominator. Since the least common multiple of 2 and 4 is 4, you need to multiply 1/2 by 2/2 (aka 1):

2) Once you have the same denominator, add the numerators and put the sum over the denominator:
