InfoPath Dev

I am relatively new to info path and have only been using it for about 3 weeks on and off. I searched the forum but couldn't find the answer that I was looking for. I am creating an form that will be hosted in SharePoint that will be used  to track sales. What I would need to be able to do is to create a from where a person would be able to submit how many tanks of gas they have available to sell. So for example some one creates an offer stating that they have 500 gallons of gas to sell. I already have the form created for them to submit how much they have available to sell. Some less would be able to reply to that form and say that they want to buy 100 gallons. I have created another view called buy that has that form design. The form would automatically update showing that their is only 400 gallons remaining for purchase. Someone else says they will buy 100 gallons and the from would update saying that their are only 300 gallons remaining for purchase. Is their anyway to be able to set that up using an info path form?

 

Thanks in advance

 Without knowing more about the design of your form, it is hard to recommend an approach - but you could put a rule on the field where you record the sold amount that resets the amount for sale (for example). Or you could just display a calculated value that subtracts the sold amount from the original amount and display that.

Hello Hillary. Thank you for the response. Sorry for the delay. This is how I wanted to form to be set up. Ill give an example. The first time someone accessing the form after it has been submitted: starting amount = 1000 purchased amount= 100 remaining amount = 900 The second time someone accessing the form after the first purchase was made: current available amount = 900 purchased amount= 100 remaining amount = 800 The third time someone wants to purchase current amount = 800 purchased amount = 100 remaining amount = 700 and so on. I have the purchase form already created and i am just trying to figure out how i would be able to do that. I have attached a copy of the form I am working on.

 Maybe just add a form load rule that recalculates everything when the item is re-opened?