1. **State the problem:** Calculate the sum of the numbers 1299, 25, 40, and 120. 2. **Formula used:** To find the sum of several numbers, use the addition formula: $$\text{Sum} = a + b + c + d$$ where $a$, $b$, $c$, and $d$ are the numbers to add. 3. **Apply the formula:** Substitute the given numbers: $$1299 + 25 + 40 + 120$$ 4. **Perform the addition step-by-step:** - First, add 1299 and 25: $$1299 + 25 = 1324$$ - Next, add 40: $$1324 + 40 = 1364$$ - Finally, add 120: $$1364 + 120 = 1484$$ 5. **Final answer:** $$\boxed{1484}$$ This is the total sum of the given numbers.