What does y+9y equal?

Question

This propably sounds dumb but is the answer to y+9y 10y or 9y :) 

Answer 1

Suppose instead of "y", you had "candy bars."

 

What's "a candy bar plus 9 candy bars?"

 

It's 10 candy bars, and the same is true for variables!

 

 

Answer 2

Doesn't sound dumb at all. It's just that we have the convention to not write "1" as a multiplier!

So y = 1y.  Now that you know this, it is easy to see that

y + 9y = 1y + 9y, and

1y + 9y + 10y

 

As you progress in algebra, many things that seemed hard in the beginning will seem easy, even obvious, later.

Don't be discouraged, we all started out knowing nothing about algebra!