need help with the math of craps

I know my math is wrong so if someone can help me I would appreciate it.

I don't have any access to simulators to test systems but I'm trying to figure out a $5 bet on pass line vs $5 bet on pass line and $5 bet on don't pass. I want to make sure I'm doing the math right which I don't think because I got a +EV on betting pass line. Also wanted to see if betting this way with a follow up after the come out roll affects which initial bet would be better. I'm new to doing this kind of math so I apologize

Well....what's your math look like?

2= -5*(1/36)
3= -5*(2/36)
4= 0
5= 0
6= 0
7= 5*(6/36)
8= 0
9= 0
10= 0
11= 5*(2/36)
12= -5*(1/36)

All added together

yeah. that's step 1 - it's right for the 1st roll. But, you can't take you bet back if that roll is a 4, 5, 6, 8, 9, or 10. How does the math look after the point is set?

That's a good question, I haven't gotten that far because I thought I was approaching it wrong. I think the math I need to do may be too advanced for me

Try this as step #2 (more complicated than step #1): For 4, 5, 6, 8, 9, and 10, figure the probability that each one is the point number set on the come out. Then multiply that by the probability of making that number again before hitting a seven. Then add all of those up, plus the total you got in step #1 (replacing the $5 with a $1). Unless I am forgetting something, that total minus 1 will be your expected net win for each dollar of your pass line wager.

After you get that worked out, you can consider what impact it would have if you take odds on your pass line bet. ;-)

Thank you I will try that. Any advice on how it would work calculating $5 pass $75 dc $5 don't pass and backing with odds? I feel like I am getting over my head and it may be easier to try to use a simulator using an idea I'm messing around with but I don't have a computer

Ignore the amounts and odds amounts for starters. Once you figure out the odds and probabilities and all that fun stuff, then just multiply by the amount you'd be wagering....or at the very least, will set the groundwork for how to figure out the math for having multiple bets going at once.