## Why Multiply Decimals? In the electrical field, multiplying decimals is a common skill. You will need it when: - Calculating power: $P = V \times I$ - Adjusting values by a decimal multiplier - Converting between units (e.g., millimeters to inches, or scaling a component’s value) ## Step-by-Step: How to Multiply Decimals ### Step 1: Ignore the decimal points Treat the numbers like whole numbers. ### Step 2: Multiply normally Use standard multiplication. ### Step 3: Count total decimal places Add the number of decimal places in both numbers. ### Step 4: Place the decimal Insert the decimal in the product, counting from the right. ### Example 1 $3.2 \times 1.5 \Rightarrow \text{Ignore decimals: } 32 \times 15 = 480$ There is **1 decimal place in each number**, so **2 decimal places total**. $480 \rightarrow 4.80$ **Final Answer: 4.80** ### Example 2 $0.75 \times 0.2 \Rightarrow 75 \times 2 = 150 \quad \text{→ move decimal 3 places} \Rightarrow 0.150$ **Final Answer: 0.15** ## Real-World Example: Power Calculation Suppose you have: - Voltage: 12.6 V - Current: 0.35 A Power: $P = 12.6 \times 0.35 = 4.41 \, \text{watts}$ Now you know the exact power draw of the device — critical information for design and troubleshooting. ## Try It Yourself 1. $4.2 \times 0.3$ 2. $0.06 \times 1.5$ 3. A circuit board receives 5.5 V at 0.2 A. What is the power?