Decibel addition equation: $${ L }_{ A }+{ L }_{ B }={ L }_{ A }+\log _{ 10 }{ (1+{ 10 }^{ \frac { -({ L }_{ A }-{ L }_{ B }) }{ 10 } }) }$$
Decibel subtraction equation: $${ L }_{ A }-{ L }_{ B }={ L }_{ A }+\log _{ 10 }{ (1-{ 10 }^{ \frac { -({ L }_{ A }-{ L }_{ B }) }{ 10 } }) }$$.
Note: Use dot "." as decimal separator.
Note: For addition and subtraction operation, LA ≥ LB
condition shall be met.