Answer:
A.) 11
Explanation:
To estimate the sum of these numbers, simply add the whole numbers of 9 and 1:
9 + 1 = 10
and then judge what the fractions will add up to roughly. 12/15 is almost 1, and it is more than 1/2, so it will round up to 11.
But to be sure you can check:
9 12/15 + 1 2/6
9 24/30 + 1 10/30 = 10 34/30 = 11 4/30 = 11 2/15