The temperature in a city one morning was 7 degrees below zero Fahrenheit. By noon it had warmed up 12 degrees. What was the temperature at noon?

1. A temperature 7 degrees below zero is written as negative 7. 2. Warming up 12 degrees means adding 12 to the starting temperature. 3. Negative 7 plus 12 has different signs, so subtract 7 from 12 to get 5, and since 12 has the larger absolute value and is positive, the result is positive. 4. The temperature at noon was 5 degrees Fahrenheit. _Source: OpenStax Prealgebra (CC BY 4.0), Ch 3 "Integers", section 3.2 Add Integers_