1. **State the problem:** Calculate the value of the expression $(-12) + 89 + (-28)$.\n\n2. **Recall the rules:** Adding a negative number is the same as subtracting its absolute value. So, $a + (-b) = a - b$.\n\n3. **Calculate step-by-step:**\n\n- Start with $(-12) + 89$. Since $89$ is positive, add $89$ to $-12$: $$-12 + 89 = 77.$$\n\n- Now add $(-28)$ to $77$: $$77 + (-28) = 77 - 28 = 49.$$\n\n4. **Final answer:** The value of the expression is $49$.