Answer #1:
11/18
Why?
Since you’re adding fractions, you need to find the lowest common denominator.
The LCD of 2 and 9 is 18. Multiply the numerator and denominator of 1/2 by 9 and for 1/9, multiply both by 2.
Now you have 9/18 + 2/18. In addition, you don’t touch the denominators when they’re the same, and just carry them over. You only add the numerators. So, 9/18 + 2/18 = 11/18.
Answer #2:
15/16
Why?
Since you’re adding fractions again, you need to find the lowest common denominator.
The LCD of 4 and 16 is 16. This means you only have to change the first fraction and not the second one. Multiply the numerator and denominator of 3/4 by 4, giving you 12/16.
Now you have 12/16 + 3/16. You don’t touch the denominators when they’re the same, and just carry them over. You only add the numerators. So, 12/16 + 3/16 = 15/16.