As many as you want
The numerator is whats being subtracted or added when you are subtracting or adding a fraction
for addition you take the sum and subtract one of the numbers being added from it and for subtraction you add the difference with the second number being subtracted so it equals the first number
-4 + 10 - 5 + 3 = 13 - 9 = 4 For problems as this, group like terms together : combine the numbers being added and similarly combine the numbers being subtracted.
In subtraction, the minuend minus the subtrahend equals the difference.
Terms of an Expression
If you are asking what the result is called, there are two terms for it: difference, and remainder.
The numbers being added are called the addends. The answer to the problem is called sum.
Addend.
The denominator (bottom number) must be the same for all the fractions being added or subtracted together.
Addition, and addends are the numbers being added.
There is no point in doing either one of these. A decibel, being the log of a ratio, is added to or subtracted from another decibel.
Addition DO'H