Balancing Ice Cream formulations (using mass balance, MSNF balance, fat balance equations + proofs in a table)

A. Desired: 800kg ice cream, 11% fat, 11% sucrose, 5% corn syrupsolids, 10.5% msnf, 0.25% stabilizer

Available: Butter - 82% fat, skim milk, condensed skim milk - 32% msnf, sucrose, corn syrup, solids, stabilizer

*Unless otherwise specified, skim milk/condensed skim milk/skim milk pwder - 0% fat; 9% snf in skim or in the skim fraction of liquid/cream/butter products

I have no idea how to do this. I tried 3 times and got a different answer every time. I also don't understand the proofs table, please help