direction: fill in the box with the missing number.
1. 1/2 + 1/3 = __ /6
2. 2/3 + 1/4 = __ /12
3. 2/4 + 3/9 = 1/ __
4. 2/5 + 1/3 = 1/___
5. 2/3 + 1/6 = __ / __​