Fill in the blanks and state the property used.
`(84+12)+96="_______"+(12+96)`

Answer

To solve the problem `(84 + 12) + 96 = "_______" + (12 + 96)`, we need to identify the property being used and fill in the blank.

### Step-by-Step Solution:

1. **Identify the Expression**: We have the expression `(84 + 12) + 96` on the left side and we need to rewrite it on the right side as `"_______" + (12 + 96)`.

2. **Use the Associative Property**: The associative property of addition states that the way in which numbers are grouped does not change their sum. In mathematical terms, this means:
\[ (A + B) + C = A + (B + C) \]
Here, we can let:
- \( A = 84 \)
- \( B = 12 \)
- \( C = 96 \)

3. **Rearranging the Expression**: According to the associative property, we can rearrange the left side:
\[ (84 + 12) + 96 = 84 + (12 + 96) \]

4. **Fill in the Blank**: Now, we can see that the left side can be rewritten as:
\[ 84 + (12 + 96) \]
Therefore, the blank can be filled with `84`.

5. **Final Statement**: The completed equation is:
\[ (84 + 12) + 96 = 84 + (12 + 96) \]
The property used here is the **Associative Property of Addition**.

### Final Answer:
The blank is filled with `84`, and the property used is the **Associative Property of Addition**.