Divide: negative 20, divided by negative 1.

1. Dividing any number by negative 1 gives that number's opposite. 2. The opposite of negative 20 is 20. 3. Since negative 20 and negative 1 share the same sign, the positive result also matches the same-sign rule. _Source: OpenStax Prealgebra (CC BY 4.0), Ch 3 "Integers", section 3.4 Multiply and Divide Integers_