When you subtract numbers, the answer is called the *difference*, and the number being subtracted is called the *subtrahend*. The number you subtract from is the *minuend*. Subtraction is shown with the minus sign (-). **Example:** In $(86 - 34 = 52)$, 86 is the minuend, 34 is the subtrahend, and 52 is the difference. **Important Rules of Subtraction:** - Unlike addition, subtraction is *not commutative* (you can’t switch the order). For example, $(5 - 3 \neq 3 - 5)$. - Subtraction is also *not associative*, so you can’t change grouping in equations. For example, $((10 - 5) - 1 \neq 10 - (5 - 1))$. **Steps for Subtracting Whole Numbers:** 1. Line up the numbers by place value (units, tens, etc.). 2. Subtract each column, starting from the right. 3. If a digit in the subtrahend is larger than the corresponding digit in the minuend, *borrow* from the next column to the left. **Example with Borrowing:** To subtract 78 from 136: - Start with the units: since $(6 - 8)$ isn’t possible without borrowing, borrow 10 from the tens place to make it $(16 - 8 = 8)$. - Move to the tens: after borrowing, the tens place becomes $(12 - 7 = 5)$. - The difference is 58. To double-check, add the difference (58) to the subtrahend (78); the result should equal the minuend (136).