1. **State the problem:** Calculate the value of the expression $$(-45) - (-30)$$. 2. **Recall the rule:** Subtracting a negative number is the same as adding its positive counterpart. So, $$a - (-b) = a + b$$. 3. **Apply the rule:** $$(-45) - (-30) = (-45) + 30$$ 4. **Perform the addition:** $$-45 + 30 = -15$$ 5. **Final answer:** $$\boxed{-15}$$