You can repeat the process several times. For example, using his two ingredients and adding a third (rice) to the ration. After pre-mixing corn and SBM (CSBM) you can use that mixture as a base but instead of going for the exact 18% go a bit higher on the interim protein, say 22%. Mix with rice with 8% protein then do the square with 18% in middle (target) and 22% Protein (corn/SBM) and 8% protein rice to get a final mix of: 45% corn, 26.5% SBM, 28.5% rice. Corn 8.9% protein at 45% = 4.00% protein SBM 44.4% protein at 26.5% = 11.76% protein Rice 8% protein at 28.5 = 2.28% protein Totals slightly above at 18.04% protein because of rounding issues doing hand calculations, but you get the broad picture.
You have ingredients and are trying to make them meet a certain nutrient requirement? How many ingredients do you have, and what type of product is it - I'm guessing it's some type of animal feed?
