Approximately how much brighter is a star of magnitude +4.0 compared to a star of magnitude +5.0?

Answer

2.512 times brighter

Since five magnitudes equal a factor of 100, a difference of just one magnitude corresponds to a brightness ratio derived from the fifth root of 100, which is approximately 2.512.

Approximately how much brighter is a star of magnitude +4.0 compared to a star of magnitude +5.0?
astronomystarbrightnessScalestellar magnitude