Yes. Presuming that you like math, of course.
I've been an employer and it DOES look good on the resume. I've never looked at a college transcript - if you're getting a real job, it's the resume that counts (actually, it's your connections, but you get the drift). It shows that you're capable of finishing stuff, and of course that you're good at math - hopefully that will translate into "you have a brain".
Most important, however, is that it gives you flexibility. You don't know now what you'll be doing in 10, 20, 30 years. This comp sci thing may not work out. Math is a pretty universal symbol for "smart", so it will help you get into something else.
If you decide on an advanced degree some time in the future, your comp. sci. stuff will be out of date, and you may have some difficulty going on. By contrast, math changes much more slowly. My math credits from my college degree in 1971 are STILL valid today, if I wanted to continue on in that field, which I don't.
And on a practical note, in many places you can use a math MINOR to teach. You may someday want (need) a teaching job, and there are a lot more math jobs than computer science teaching jobs. When you have kids, EVERYBODY gives some thought to teaching. Trust me.