1. **State the problem:** Calculate the value of $1 - 0.0121$. 2. **Formula used:** Subtraction of decimal numbers is straightforward: subtract the smaller number from the larger number digit by digit. 3. **Intermediate work:** $$1.0000 - 0.0121 = 0.9879$$ 4. **Explanation:** We align the decimal points and subtract each digit starting from the right: - $0 - 1$ requires borrowing. - After borrowing and subtracting all digits, the result is $0.9879$. 5. **Final answer:** $$1 - 0.0121 = 0.9879$$