\[\boxed{\mathbf{Страница\ 10.}еуроки - ответы\ на\ пятёрку}\]
\[\boxed{\mathbf{29.}}\]
\[(5 + 8) \cdot 4 = 52\]
\[1)\ 5 \cdot 4 = 20\]
\[2)\ 8 \cdot 4 = 32\]
\[3)\ 20 + 32 = 52\]
\[(3 + 7) \cdot 8 = 80\]
\[1)\ 3 \cdot 8 = 24\]
\[2)\ 7 \cdot 8 = 56\]
\[3)\ 24 + 56 = 80\]
\[(9 + 2) \cdot 7 = 77\]
\[1)\ 9 \cdot 7 = 63\]
\[2)\ 2 \cdot 7 = 14\]
\[3)\ 63 + 14 = 77\]
\[(4 + 6) \cdot 3 = 30\]
\[1)\ 4 \cdot 3 = 12\]
\[2)\ 6 \cdot 3 = 18\]
\[3)\ 12 + 18 = 30\]
\[\boxed{\mathbf{30.}}\]
\[17 \cdot 2 = (10 + 7) \cdot 2 = 34\]
\[1)\ 10 \cdot 2 = 20\]
\[2)\ 7 \cdot 2 = 14\]
\[3)\ 20 + 14 = 34\]
\[15 \cdot 8 = (10 + 5) \cdot 8 = 120\]
\[1)\ 10 \cdot 8 = 80\]
\[2)\ 5 \cdot 8 = 40\]
\[3)\ 80 + 40 = 120\]
\[\boxed{\mathbf{31.}}\]
\[1\ дм\ 7\ см = 17\ см\]
\[17 \cdot 9 = (10 + 7) \cdot 9 = 153\ \left( см^{2} \right).\]
\[1)\ 10 \cdot 9 = 90\]
\[2)\ 7 \cdot 9 = 63\]
\[3)\ 90 + 63 = 153\]
\[Ответ:153\ см^{2}.\]