A decibel (link to: https://en.wikipedia.org/wiki/Decibel) is a unit, where we compare two acoustic values. Because the ratio is logarithmic the rules for logarithms apply, not the rules for simple arithmetic. The consequence is that a difference of 10 dB (decibels) is very large from an energetic standpoint. 10 dB for the human ear means something is twice as loud or quiet.