\[\boxed{\text{27.}}\]
\[24\ :8 = 3\]
\[56\ :7 = 8\]
\[28\ :4 = 7\]
\[48\ :6 = 8\]
\[64\ :8 = 8\]
\[81\ :9 = 9\]
\[\boxed{\text{28.}}\]
\[63\ :7 > 56\ :7\]
\[48\ :6 > 24\ :4\]
\[5 \cdot 7 < 6 \cdot 6\]
\[6 \cdot 8 < 7 \cdot 8\]
\[42\ :7 < 45\ :5\]
\[6 \cdot 8 = 8 \cdot 6\]
\[\boxed{\text{29.}}\]
\[40\ :8 = 5\ (стаканчиков) -\]
\[мороженого\ можно\ купить\ на\ \]
\[40\ рублей.\]
\[Ответ:5\ стаканчиков.\]
\[\boxed{\text{30.}}\]
\[8 \cdot 2 = 16\]
\[8 \cdot 3 = 24\]
\[8 \cdot 4 = 32\]
\[8 \cdot 5 = 40\]
\[8 \cdot 6 = 48\]
\[8 \cdot 7 = 56\]
\[8 \cdot 8 = 64\]
\[8 \cdot 9 = 72\]
\[9 \cdot 2 = 18\]
\[9 \cdot 3 = 27\]
\[9 \cdot 4 = 36\]
\[9 \cdot 5 = 45\]
\[9 \cdot 6 = 54\]
\[9 \cdot 7 = 63\]
\[9 \cdot 8 = 72\]
\[9 \cdot 9 = 81\]