The only bets that pay true odds are odds bets associated with the Pass Line, Don't Pass, Come, and Don't Come bets. This means that the payoff ratios on these bets are a direct reflection of the true odds. For instance, there are 6 ways to roll a 7, and 5 ways to roll an 8, so the true odds of rolling a 7 versus an 8 are 6 to 5. Therefore, an odds bet on the 8 will pay $6 for every $5 you bet.
BREAKING BETS DOWN
POINT 6 OR 8
PAYS 6:5
Technically, paying off odds at 6 to 5 simply means your paying the bet plus 20% How quick can you pay $840 at 6 to 5 odds? What is 20% of 840? Now add that figure to $840.....Not all that simple, is it? It is for some, but not me. When I went to dealing school years ago, I remember my instructor teaching me that each red chip pays $6 and each green chip pays $30. That also works to a degree. Then I remember a player that bet about 12 green chips and 14 red in odds one day and I couldn't compute the payoff fast enough with everyone staring at me.
So pick a way that works for you.
 Odds bet plus 20%,
 Each green pays 30, each red pays 6
 The 'First Nine'
 Combination of all the above
Let us start with what I call the 'First Nine'
Paying the true odds
6:5
6:5
5 PAYS 6 IS THE "KEY" BET
Examples of breaking a bets down:
35=42
Within the $35 odds bet you have a $30 bet and a $5 bet
(30=36, 5=6, 36+6=42)
45=54
Within the $45 odds bet you have a $40 bet and a $5 bet
(40=48, 5=6 , 48+6=54)
65=78
Within the $65 odds bet you have a $60 bet and a $5 bet
(60=72, 5=6 , 72+6=78)
85=102
Within the $85 odds bet you have a $80 bet and a $5 bet
(80=96, 5=6 , 96+6=102)
Popular 6 to 5 odds bets
25=30
Within the $25 odds bet you have a $20 bet and a $5 bet
(20=24, 5=6 , 24+6=30)
75=90
Within the $75 odds bet you have a $70 bet and a $5 bet
(70=84, 5=6 , 84+6=90) or each $25 Green chip pays $30
Examples of breaking a bets down:
35=42
Within the $35 odds bet you have a $30 bet and a $5 bet
(30=36, 5=6, 36+6=42)
45=54
Within the $45 odds bet you have a $40 bet and a $5 bet
(40=48, 5=6 , 48+6=54)
65=78
Within the $65 odds bet you have a $60 bet and a $5 bet
(60=72, 5=6 , 72+6=78)
85=102
Within the $85 odds bet you have a $80 bet and a $5 bet
(80=96, 5=6 , 96+6=102)
Popular 6 to 5 odds bets
25=30
Within the $25 odds bet you have a $20 bet and a $5 bet
(20=24, 5=6 , 24+6=30)
75=90
Within the $75 odds bet you have a $70 bet and a $5 bet
(70=84, 5=6 , 84+6=90) or each $25 Green chip pays $30
Let's turn up it shall we?
Here's how it works. First, we move a decimal point around a little.
10 pays 12 thus 100 must pay 120,
(1000 = 1200)
20 pays 24 thus 200 must pay 240,
(2000 = 2400)
30 pays 36, 300 = 360,
(3000 = 3600)
You get the picture....
Ready?
120=144
Within the $120 odds bet you have a $100 bet and a $20 bet
100 pays 120
20 pays 24
120 +24 = 144
330=396
Within the $330 odds bet you have a $300 bet and a $30 bet
300 pays 360
30 pays 36
360 + 36 = 396
225=270
Within the $225 odds bet you have a $200 bet and a $25 bet
200 pays 240
25 pays 30
240 + 30 = 270
410=492
Within the $410 odds bet you have a $400 bet and a $10 bet
400 pays 480
10 pays 12
48 + 12 = 492
Let's play around with the numbers....
If $5 pays $6 then $50 pays $60
If $15 pays $18 then $150 must pay $180
If $25 pays $30 then $250 must pay $300
175=210
Within the $175 odds bet you have a $100 bet and a $75 bet
100 pays 120
75 pays 90
120 + 90 = 210
One could look at 150 within paying 180 and 25 pays 30
180 + 30 = 210
190 = 228
100 pays 120
90 pays 108
120 + 108 = 208
or
150 pays 180
40 pays 48
180 + 48 = 228
If $5 pays $6 then $50 pays $60
If $15 pays $18 then $150 must pay $180
If $25 pays $30 then $250 must pay $300
175=210
Within the $175 odds bet you have a $100 bet and a $75 bet
100 pays 120
75 pays 90
120 + 90 = 210
One could look at 150 within paying 180 and 25 pays 30
180 + 30 = 210
190 = 228
100 pays 120
90 pays 108
120 + 108 = 208
or
150 pays 180
40 pays 48
180 + 48 = 228
Remember that $840 bet we just discussed in the intro?
800 pays 960, 40 pays 48
960 + 48 = 1008
$840 pays $1008
Looking back to those old days as a break in dealer, the player that bet
12 green ($300) and 14 red ($70)
300 pays 360 and 70 pays 84,
360 + 84 = 444
That $370 odds bet paid $444
800 pays 960, 40 pays 48
960 + 48 = 1008
$840 pays $1008
Looking back to those old days as a break in dealer, the player that bet
12 green ($300) and 14 red ($70)
300 pays 360 and 70 pays 84,
360 + 84 = 444
That $370 odds bet paid $444
6:5 ODDS BET PLUS 20%
Just about anyone can compute 10% of a number, so simply double that to get 20%
Ready?
Ready?
130 pays 156
20% of 130 = 26
130 + 26 = 156
160 pays 192
20% of 160 = 32
160 + 32 = 192
240 pays 288
20% of 240 = 48
240 + 48 = 288
275 pays 330
20% of 275 = 55
275 + 55 = 330
That one wasn't so easy was it?
10% of 275 is 27.50
Double 27.50 on a live game then add to bet
Yikes!
Experienced craps dealers see...
270 broken down
250 = 300 & 25 = 30
300 + 30 = 330
Many ways to figure out payoffs
Then there's this guy, big ass stack of red for his odds behind the pass line. Hmmm, you or the dealer before you apparently paid this guy a ton of red. Now the dice are hot and he....bets it!

It's cool, its easy. When the point rolls (The 8) you will simply run down the stack five high thinking at the same time that each small stack of 5 red you cut down will pay $30
In your head as you cut into each stack, 30, next stack, 60,...90
30,60,90....120 I'm counting as I go
All kinds of ways to pay off at 6:5
Each green pays 30
Each green pays 30
This guy again
Now he bet a rainbow
in odds!
Now he bet a rainbow
in odds!
Same thing, I'll count as I go....
Each small stack green =120
Each small stack green =120
Now the red....
I count as I go...
I count as I go...
Video below will show more tricks of the trade