Which star is brighter -2 or -3?
The way stellar magnitude works, a smaller number is associated
with increased brightness. Since -3 < -2, a magnitude -3 star
would be brighter than a magnitude -2 star. Each decrease in
magnitude by 1 means in increase in brightness by a factor of about
2.5119. Equivalently, each decrease in magnitude by 5 means an
increase in brightness by a factor of 100.
Incidentally, the brightest star in the sky (Sirius) has an
apparent magnitude of only about -1.5.