## Why Is This Important? In the electrical field, precision is critical. Whether you are: - Calculating total voltage drop - Summing wire lengths - Subtracting tolerances - Adjusting values for resistors or measurements You need to **add and subtract decimals correctly** to avoid costly errors. ## Step-by-Step: Adding or Subtracting Decimals ### Step 1: Line up the decimal points Decimals must be aligned just like whole numbers are stacked by place value. ### Step 2: Fill in zeros Make sure each number has the same number of decimal places before calculating. ### Step 3: Add or subtract as usual #### Example 1: Adding Decimals $12.75 + 3.4 \Rightarrow \begin{align*} 12.75 \\ +03.40 \\ \hline 16.15 \end{align*}$ **Answer: 16.15** #### Example 2: Subtracting Decimals $9.6 - 2.35 \Rightarrow \begin{align*} 09.60 \\ -02.35 \\ \hline 07.25 \end{align*}$ **Answer: 7.25** ## Real-World Example: Total Conduit Length You measure and cut three conduit sections: - 12.25 ft - 7.6 ft - 3.15 ft Add them together: $12.25 + 7.60 + 3.15 = 23.00 \, \text{ft}$ Now you know exactly how much conduit to order, helping you avoid waste and extra cost. ## Try It Yourself 1. Add: $8.5 + 2.75$ 2. Subtract: $10.00 - 6.375$ 3. You measure a wire length of 15.4 ft and trim off 2.95 ft. What length remains?