Thanks, CPhill.
I usually just google what I want a picture of. (In this case, I just googled "number line generator")
Then, if I want to edit the picture at all, I just use a paint program I have on my computer called paint.net
It's not necessarily meant for math editing, but I like the different paint options it has. Here's the link to their website if you want to check it out: http://www.getpaint.net/index.html
According to Wikipedia, "Mathematics is the study of topics such as quantity, numbers, structure, space, and change. There is a range of views among mathematicians and philosophers as to the exact scope and definition of mathematics."
Read more about it here: http://en.wikipedia.org/wiki/Mathematics
We have (0.15)2x100
Since there is no mathematical symbol between the (0.15) and 2, it means to multiply.
0.15*2*100 --- * means multiply in computer language, so as to not confuse it with the algebraic unknown x
.3*100
30
To check this, you can always put the question it in the website's calculator!
You can find this here: http://web2.0calc.com/