How do you add decimals?

The most important thing is that you line up the decimal points and then add

Look at this web page

http://www.mathsisfun.com/adding-decimals.html

It's just like adding w/out a decimal...for example 12.45+30.45632

you work the problem like this...

$${\mathtt{30.456\: \!32}}{\mathtt{\,\small\textbf+\,}}{\mathtt{12.45}} = {\mathtt{42.906\: \!32}}$$ 

What I usually do to help me is I have to have an equal number of decimals so that I can read it easier...so I add zeros b/c you can add as many zeros to a decimal w/out changing it's value.

Hope I helped.