Can someone just check this through:

Let's say blinds are 150 and 300

SB calls so there's 600 in the pot (2 players)

Flop comes up and I'm on a straight draw - I need any Ace

Other player raises it 300.

Now here's the bit that I need checking:

Using the rule of 2-4, I've got 4 cards that I need ... which is around about 10-1 chance (4 x 2 + 10 = 10%).

So therefore, to justify calling I need 3,000 to be in the pot. The pot is obviously a long way short of that (there's only 900 in there), so the correct decision is to fold.

Is that the correct way to work out pot odds?

Thanks for your help,