I have a number in cell A1, B1, and C1. Cell D1 contain the formula to average A1, B1, and C1. I need to insert three new rows, so A1, B1, C1, and D1, now become D1, E1, F1, and G1 respectively. I want the average formula that was originally in cell D1, now G1, to again average the new values in A1, B1, and C1. How do keep the reference to A1, B1, and C1 so that the average formula always looks at those cells as new cells are inserted?