there were 21 5/8 yards of wire on a spool. After a customer bought 3 3/4 yards of wire from the spool, how many yards were left?
There will be \(21\frac58-3\frac34\) yards left.
\(\,21\frac58-3\frac34 \\~\\ =(21+\frac58)-(3+\frac34) \\~\\ =21+\frac58-3-\frac34 \\~\\ =21-3+\frac58-\frac34 \\~\\ =18+\frac58-\frac68 \\~\\ =18-\frac18 \\~\\ =17\frac78\)
+29 
