hi! i am going on a camping trip with my 2 teenage sons and would like to have some extra food and water to make sure we dont run out while out in the wilderness 
That sounds like fun.  Are you planning on hanging out at the campsite or hiking?
we were planning on doing a lot of hiking. Due to this we will need extra food and water, how about I take all the extra food and 1 of the water, you can have the rest? 
I also am planning on hiking a lot. I can give you 2 food, and one water if  you give me 2 firewood?
So i would take 2 food, 2 water and a firewood? that would work great for me! 
No, not exactly, but close.  I would give you 2 food, 1 water and 1 firewood.  Does that work?  I know with teenagers the food is very important. 
it is but so is water, would you be willing to trade the firewood for the water, so i take 2 food and 2 water and you can have the rest? 
Yes, that would work for me.   I really don't like to be cold.  If I don't sleep, there would be no hiking for me.  I  also enjoy having extra firewood to roast marshmallows and sometimes even invite other campers i meet to join me for a meal.  
OOH smore's that sounds good, sounds like we have a deal - i will take 2 food and 2 water you get 1 food 1 water and 3 firewood! 
Yes. have a great trip.  I remember when my boys were teenagers and couldn't get enough food.  Have a great time.