109*108*...*92*91 126*124*122*120*...*92 Why would ----------------- = ----------------------- ? 127*125*... 93*91 127*126*125*124*...*110 cross multiply - then (127*126*125*124*...*110) * (109*108*...*92*91) = (127*125*... 93*91) * (126*124*122*120*...*92) since the LHS and RHS lines are both 127! / 90! (highs and then lows on the LHS, odds and then evens on the RHS) more later, cal