We have the following:
[tex]a\frac{b}{c}=\frac{a\cdot c+b}{c}[/tex]therefore:
[tex]\begin{gathered} 21\frac{3}{8}=\frac{21\cdot8+3}{8}=\frac{168+3}{8}=\frac{171}{8} \\ 4\frac{1}{2}=\frac{4\cdot2+1}{2}=\frac{8+1}{2}=\frac{9}{2} \end{gathered}[/tex]now, we divde to know the amount:
[tex]\frac{\frac{171}{8}}{\frac{9}{2}}=\frac{171\cdot2}{8\cdot9}=\frac{342}{72}=4.75\cong4[/tex]Therefore, the answer is 4 whole tiles
