On both apparent and absolute magnitude scales, the smaller the magnitude number, the brighter the star; the larger the magnitude number, the fainter the star. The brightest stars, on either scale, have negative magnitude numbers. The variation in brightness (Δ L) between two stars is calculated by subtracting the magnitude number of the brighter star (m b) from the magnitude number of the fainter star (m f), then using the difference as an exponent for the base number 2.512; that is to say: