You can put this solution on YOUR website!
First, you must add the numbers of marbles together. The equation would look like this: 6+10+18+5= ? Once you have that answer, you must look at how many of the marbles are red. That answer would look like this: red/? They numerator is the number of red marbles and the denominator is the marbles added all together. Then you must look at how many marbles are blue. That answer would look like this: blue/? After you have done that, you are almost done. Now you must add the two fractions together. red/? + blue/? = redblue/? Finally, you must simplify. If you need assistance with that, go to google and type in "simplifying fractions" in the box, and click the first link.
I hope this helps!