Thanks for all the help

I wrote three little programs for my TI85 calculator

the first program

you input, preboil gravity, preboil volume, and final volume

and gives the OG

the second program

you input, target gravity, target volume, preboil volume, and preboil gravity

and gives me lbs of DME to add, or the final volume needed to hit the OG

the third program

you input, final volume, target gravity, preboil volume

and gives the preboil gravity need to hit the OG