Luann has a piece of ribbon that is 1 yard long. she cuts 33 inches off to tie a gift box. how many inches of ribbon are not used?

First, we convert the given initial length of the ribbon by the conversion factors,
                                          1 yd  = 3 ft
                                           1 ft = 12 inches
Converting,
                                        (1 yd)(3 ft/ 1 yd)(12 in/1 ft) = 36 in
Since Luann used 33 inches, the length of the unused ribbon is 3 inches.