I dunno about math, but the English PRAXIS was pretty easy for me. And you just have to pass it.

Yes, but... it's a TEST! How can I live with myself if I don't do really well? Of course, this will mean remembering the difference between the associative and commutative properties. Which shouldn't be that difficult, it's just I have a block. I think associative is (a+b)+c = a+(b+c) and commutative is a+b = b+a. But I'm not sure.

I think associative is (a+b)+c = a+(b+c) and commutative is a+b = b+a. But I'm not sure.

That's right. Associative is that you can change which numbers associate with each other first. Commutative is that the numbers can move around, like commuting from one side of the plus sign to the other. (At least, that's how I'm able to remember it.)

And what about transitive? Is that a=b implies a+c=b+c?

ETA: Of course I could google it. But I like talking to you people!

Transitive is a=b and b=c -> a=c (or with < or > replacing the =s)

Hil is very clever. All I can think of when I see "commutative principle" is "What's purple and commutes?"

Ans: An Abelian grape

And that may well summarize What I Learned in Abstract Algebra.

Equality is transitive because a = b and b = c implies that a = c.

Okay, that's what I thought. So then what property is involved in the proof that a+z = b+z => a=b?

Ignoring the disturbing math talk, to say g'night. I'll be back tomorrow morning!

So then what property is involved in the proof that a+z = b+z => a=b?

Quite.

So then what property is involved in the proof that a+z = b+z => a=b?

I think that's the inverse property, since what you're doing there is adding the inverse of z to each side.

G'night, Erin!

Looking again at the question, I think they were looking for associative, for the step from (a+z)+-z=(b+z)+-z to a+(z+-z)=b+(z+-z). Interesting. I wouldn't have thought to make that two steps, but I guess it makes sense.

Anyway, thank you.