### Great Big Book of Algebra

Friday, December 19, 2008
Kat : Hey Rina!
Rina : Hey Kat.
Kat : Why are you sad?
Rina : Because I'm going to get in trouble when i get home.
Kat : Really? why?

Rina : Because I got a low mark in math on my report card.

Kat : Why is that? Don't you understand it?

Rina : Well, I don't really understand algebra and algebraic equations.
Kat : Oh really? Well, let me help you! its fairly easy.

Rina : Really? Okay thanks!

Kat : No problem! Well, let's get started!

Rina : Okay, well i remember us having this question that really tricked me. I'm pretty sure all we had to do was simplify it. Though i never really understood how.

Kat : Oh, well okay then, what was the question?

Rina : I think it was n+3-5n+12.

Kat : That's easy. The first step to simplifying this expression is to combine the like terms.
Rina : How do i do that? do i just put together the ones that are the same or similar to each other?
Kat : Exactly! you're correct. All you have to do is to combine the ones that are similar to each other.
Rina : Oh, okay so all I have to add first is n and 5n?
Kat : Yes. But since there is a negative sign before the 5n, which means that it is negative 5n. So when you add the n to the -5n, you get a -4n.

Rina : I get it! Okay, so whats the next step?

Kat : Alright, now the other ones that are the same.

Rina : 3 and 12?

Kat : Correct. 3+12 is?..

Rina : 15! 3+12 is 15!

Kat : Good job! So now that you have both of the numbers, all you have to do is add them together but don't solve it.

Rina : Don't solve it?
Kat : Don't solve it because there's no equal sign.
Rina : Right! which means it's not an equation because its an expression!
Kat : Exactly! So, do you know what the answer to the question is now?

Rina : Yes. When you simplify n+3-5n+12, you get 4n+12.

Kat : Good Job. You're right.
Rina : Thanks Kat. You're a really good friend!

Kat : You're welcome. I hope you get a better mark next time!

Rina : Me too!