What is the difference of 21 15/16 minus 18 3/4 ?
\(21 \frac{15}{16}-18 \frac{3}{4}=21 \frac{15}{16} - 18 \frac{3 \times 4}{4 \times 4}=21 \frac{15}{16}-18 \frac{12}{16}=\boxed{3 \frac{3}{16}}\)