Our goats are pet wethers, and I give them all our veggie peelings except raw potato. They also have fruit thats gone past it best, stale cake and bread (in moderation) and digestive biscuits as a treat (if I have to get them in for some reason).
3. Click the lower right corner of cell C1 and drag the formula down. Result: 4. To change the negative numbers to zero but leave the positive numbers unchanged, instead of =A1-B1, use =MAX(0,A1-B1) and drag the function down. Result: Explanation: the MAX function returns the maximum of two values. If the result of the formula is negative, the function returns 0.
Excel formula to return the number from a column letter (From @A. Klomp's comment above), where cell A1 holds your column letter(s): =column(indirect(A1&1)). As the indirect function is volatile, it recalculates whenever any cell is changed, so if you have a lot of these it could slow down your workbook.