Smaller numbers mean brighter sources
For matched passbands and calibration, m₁−m₂=−2.5log₁₀(F₁/F₂), where F is received flux. A factor of 100 in flux corresponds to five magnitudes, with the brighter source having the smaller number.
Values need not be positive integers. Bright sources can have negative magnitudes and faint telescopic targets extend beyond naked-eye classes. Zero magnitude is a calibration reference, not zero received light.
The passband matters
One star can have different magnitudes through different filters. Differences between photographic and visual response helped motivate calibrated passbands such as U, B and V.
Catalogue comparisons require the photometric system, filter and zero point. Sorting an infrared magnitude against a visible-band value does not by itself compare brightness in one common band.
Received brightness and intrinsic emission
A nearby low-luminosity star can look brighter than a distant luminous one. For a nearby isotropic source without absorption, flux follows an inverse-square distance relation; apparent magnitude does not remove distance effects.
Absolute magnitude places stellar comparisons at a common distance. Absorption and variability also matter, so one apparent-magnitude value alone does not establish size, age or total energy output.