Question: Match the equations to the correct property
1) (5 + 2) + 8 = 5 + (2 + 8)
2) 5 + 4 = 4 + 5
3) 5 \cdot 1 = 5
4) 0 + 2 = 2
5) 8(0) = 0
6) 2 (3 + 5) = 2 \cdot 3 + 2 \cdot 5
Write the property that justifies each step in the calculation.
7) 7.5x + [2.8 + (− 3.2x)]
7.5x + [− 3.2x + 2.8]
[7.5x + (− 3.2x)] + 2.8
4.3x + 2.8
1. **State the problem:** We need to identify the property of each equation and each step in the simplification.
2. **Properties for equations 1 to 6:**
- Equation 1: $ (5 + 2) + 8 = 5 + (2 + 8) $ is the **Associative Property of Addition** because it changes grouping without changing the sum.
- Equation 2: $ 5 + 4 = 4 + 5 $ is the **Commutative Property of Addition** because it changes the order of addends.
- Equation 3: $ 5 \cdot 1 = 5 $ is the **Multiplicative Identity Property** because multiplying by 1 leaves the number unchanged.
- Equation 4: $ 0 + 2 = 2 $ is the **Additive Identity Property** because adding zero leaves the number unchanged.
- Equation 5: $ 8(0) = 0 $ is the **Multiplicative Property of Zero** because any number times zero is zero.
- Equation 6: $ 2 (3 + 5) = 2 \cdot 3 + 2 \cdot 5 $ is the **Distributive Property** because multiplication is distributed over addition.
3. **Properties for simplification steps in problem 7:**
Given expression: $$7.5x + [2.8 + (-3.2x)]$$
- Step 1 to 2: $$7.5x + [2.8 + (-3.2x)] = 7.5x + [-3.2x + 2.8]$$
This is the **Commutative Property of Addition** inside the brackets, changing order of terms.
- Step 2 to 3: $$7.5x + [-3.2x + 2.8] = [7.5x + (-3.2x)] + 2.8$$
This is the **Associative Property of Addition**, regrouping terms.
- Step 3 to 4: $$[7.5x + (-3.2x)] + 2.8 = 4.3x + 2.8$$
This is **Combining Like Terms** by adding coefficients: $$7.5x - 3.2x = 4.3x$$.
4. **Summary of properties:**
| Equation/Step | Property Name |
|--------------|----------------|
| 1 | Associative Property of Addition |
| 2 | Commutative Property of Addition |
| 3 | Multiplicative Identity Property |
| 4 | Additive Identity Property |
| 5 | Multiplicative Property of Zero |
| 6 | Distributive Property |
| 7 Step 1-2 | Commutative Property of Addition |
| 7 Step 2-3 | Associative Property of Addition |
| 7 Step 3-4 | Combining Like Terms |
**Final answer:** The properties justifying each step are as above.