If a > b and c > d, then a + c > b + d. this state is [always, sometimes, never] true

The answer is Always true. because A is greater than B so put it this way if A=2 and B =1 then 2>1 same goes for C>D so if A+C would have to be greater than B+D for instance 2+2>1+1 or 4>2 so
If A>B and C>D, then A+C>B+D Always  true.

It is important because sometimes ur dna needs to multiply