12. \( \begin{array}{r}8,109 \\ -\quad 3,825 \\ \hline\end{array} \)

To solve the subtraction problem \( 8,109 - 3,825 \), we will perform the calculation step by step. 1. **Align the numbers**: Write the numbers one under the other, aligning them by their place values (units, tens, hundreds, thousands). ``` 8109 - 3825 ``` 2. **Subtract from right to left**: - **Units place**: \( 9 - 5 = 4 \) - **Tens place**: \( 0 - 2 \) (we need to borrow 1 from the hundreds place, making it \( 10 - 2 = 8 \)) - **Hundreds place**: After borrowing, we have \( 0 - 8 \) (which is now \( 10 - 8 = 2 \)) - **Thousands place**: \( 7 - 3 = 4 \) (after borrowing, the 8 becomes 7) 3. **Write down the result**: - Combining all the results from each place value, we get: ``` 8109 - 3825 ------ 4284 ``` Thus, the result of \( 8,109 - 3,825 \) is \( 4,284 \).