When you hold the tape in your left hand so you can mark with your right hand, the numbers on most tapes read upside down. That can lead to confusion, especially for unmarked fractions. Solution: Rather than try to figure out which mark is 3/8 and which is, 5/8 for example, get a left-reading measuring tape or one that reads from both sides, as shown.FastCap 16' Lefty/Righty,