Math Argument

You and your mathematical friend were just walking around the neighborhood when you see 4 of your friend's other friends arguing.

He tells you their names (Alfred, Sally, Michael, and David). You've heard about these friends, so you know that A lfred always speaks a number equal to a constant A DDED TO the real number. You also know that S ally speaks a constant S UBTRACTED FROM the real number, M ichael speaks a constant M ULTIPLIED BY the real number, and that D avid D IVIDES the real number by a constant before speaking. However, you don't know what their assigned constants are nor do you know whether they're positive or not.

After they say hi in unison, this is what happens:

Alfred says "Be cautious! Sally always says the value which is 2 less than what she means"

David responds "Whoa! Let's not forget that you always say the value which is 0.25 more than what you actually mean. So just shut up!"

Michael then says to them "Daniel, can you please recall that you still say 12.5 percent of what you mean?"

Sally says "Alfred, can we all please apologize to each other?"

Alfred says "No way, Sally!"

Then Alfred looks at you and says "Michael multiplies all of his numbers by 3. Stay away from him!"

Before you go, your friend tells you that actually, two of the friends who are arguing in front of you end up doing nothing to the real number and say the same value they mean.

What constant does Alfred add to his numbers?