Copy the first & third columns in to another test file. Its very urgent please

Hello friends!
Here is the scenario.
I have a flat file named FILE1.TXT with multiple columns and comma as delimiter.
Now my task is to create another file called FILE2.TXT which contains the FIRST & THIRD column values from FILE1.TXT separated by comma.
Which mean i am creating a new files with only two columns which are 1st and 3rd. Ex:

FILE1.TXT
1,2,3,4,5,6,7,8,9
1,2,3,4,5,6,7,8,9
1,2,3,4,5,6,7,8,9
1,2,3,4,5,6,7,8,9
1,2,3,4,5,6,7,8,9

Now after creating another file FILE2.TXT it should look like this:

FILE2.TXT
1,3
1,3
1,3
1,3
1,3

Using Unix create a script for this. Please help me out as this is very urgent. I would be very grateful to you people.

What is the urgency?

As a hint,

sed y/,/\ /

might be a good starter.

awk -F"," '{print $1",",$3}' FILE1.TXT >FILE2.TXT

if its urgent, there are 2 possibilities, 1) assignment due, 2) work dead line

... and the computer controls a nuclear power station?

Thanks a lot Jacoden!
This worked!
Thanks to rest of the people too. Anyway , have to meet some deadlines.
Thanks again.