Answer:
11. D Estimated > actual
12.
If you can include negative numbers, the answer is yes.
If you cannot include negative numbers, the answer is no.
Explanation:
11.
Let's look at 7 9/12: 9/12 is closer to 1 than to zero. It is greater than half. 7 9/12 is rounded up to 8.
Now look at 2 11/12: 11/12 is almost 1, so 2 11/12 rounds up to 3.
The estimated product is 8 * 3 = 24.
The actual product uses 7 9/12 instead of 8, and 2 11/12 instead of 3. Since the numbers used in the actual calculation are both lower than those used in the estimate, the actual calculation will be less than the estimate.
Answer: D Estimated > actual
12.
Answer: it depends
If you have learned about negative numbers, and you can include negative numbers in the explanation, then the answer is yes. For example:
-5 1/3 + 7 1/3 = 2
If you have not learned about negative numbers, and negative numbers are not allowed in the explanation, then the answer is no. You are adding two mixed numbers. Each mixed number must be at least 1 and a fraction. Once you add the two 1's, you already have 2, so by adding the fractions, you will end up with more than 2.