Subtraction of Integers
Example 1: 7 - 13 = ?
| Rewrite the problem using the definition of subtraction: (a - b) = a + (-b) = a + the opposite of b |
7 - 13 = 7 + (-13) |
| Now, add the two integers following the rules for addition of integers. |
7 + (-13) = ? |-13| + |7| = 13 - 7 = 6 -13 has the larger absolute value, so the answer will be negative. Thus, 7 - 13 = -6 |
Example 2: 9 - (-15) = ?
| Rewrite the problem using the definition of subtraction: (a - b) = a + (-b) = a + the opposite of b |
9 - (-15) = 9 + 15 |
| Now, add the two integers following the rules for addition of integers. |
9 + 15 = 24
Thus, 9 - (-15) = 24 |