2. Calculate the following. a. \( (5+7)+8=\square+(7+8) \) c. \( 9+(1+4)=(\square+\square)+4 \) e. \( (12+13)+11=12+(\square+11) \)

Let's solve each part by applying the **associative property of addition**, which states that how numbers are grouped in an addition operation does not change their sum. In other words: \[ (a + b) + c = a + (b + c) \] ### Part a \[ (5 + 7) + 8 = \square + (7 + 8) \] **Solution:** Using the associative property: \[ (5 + 7) + 8 = 5 + (7 + 8) \] So, the blank (\(\square\)) is **5**. **Answer:** \[ \square = 5 \] --- ### Part c \[ 9 + (1 + 4) = (\square + \square) + 4 \] **Solution:** Again, applying the associative property: \[ 9 + (1 + 4) = (9 + 1) + 4 \] So, the blanks are **9** and **1**. **Answer:** \[ \square = 9 \quad \text{and} \quad \square = 1 \] --- ### Part e \[ (12 + 13) + 11 = 12 + (\square + 11) \] **Solution:** Applying the associative property: \[ (12 + 13) + 11 = 12 + (13 + 11) \] So, the blank (\(\square\)) is **13**. **Answer:** \[ \square = 13 \] --- ### Summary of Answers - **a.** \(\square = 5\) - **c.** \(\square = 9\) and \(\square = 1\) - **e.** \(\square = 13\)