## What Is Decimal Division? Dividing decimals means finding how many times one decimal number fits into another. In electrical work, you might divide decimals to: - Find resistance when voltage and current are known - Calculate efficiency or ratios - Determine cost per unit of power or energy ## Step-by-Step: How to Divide Decimals ### Step 1: Remove the Decimal from the Divisor If the divisor (the number you are dividing by) is not a whole number, move its decimal point to the right until it becomes one. Then move the decimal point in the dividend (the number being divided) the **same number of places**. Example: To solve $6.4 \div 0.2$ move the decimal in both numbers one place to the right: - $6.4 \rightarrow 64$ - $0.2 \rightarrow 2$ Now solve $64 \div 2$. ### Step 2: Perform Long Division as Usual Once the decimals are shifted and you are working with whole numbers, divide just like you would in basic arithmetic. Example: $64 \div 2 = 32$ If needed, you can use long division manually or a calculator. Make sure to **include the decimal point in the final answer** if your dividend had one. ### Step 3: Place the Decimal in the Quotient The decimal point in the quotient (the answer) goes directly above its new position in the dividend. If you're using a calculator, this is done automatically. If you're doing long division by hand, remember to place the decimal carefully before writing your final answer. ### Example Find ( $4.8 \div 1.2$ ) $ 1.2 \rightarrow 12 \quad (\text{move decimal 1 place}) $ $ 4.8 \rightarrow 48 \quad (\text{move decimal 1 place}) $ Now divide: $ 48 \div 12 = 4 $ Answer: 4 ## Real-World Example: Ohm’s Law Using Ohm’s Law: $ R = \frac{V}{I} $ If ( $V = 12.6 \text{ V}$ ) and ( $I = 0.35 \text{ A}$ ): $ R = 12.6 \div 0.35 $ Move each decimal two places: $ R = 1260 \div 35 = 36 $ Resistance is 36 Ω This is a common use of decimal division in testing and troubleshooting. ## Try It Yourself 1. ( $7.5 \div 0.5 = ?$ ) 2. ( $2.4 \div 0.3 = ?$ ) 3. A 9.6 V battery powers a circuit drawing 0.4 A. What is the resistance? ## Summary - Move the decimal in both numbers until the divisor is a whole number. - Divide normally. - Place the decimal in the quotient directly above its position in the dividend. - Decimal division is used in Ohm’s Law and efficiency calculations.