Tính nhanh tích sau: (-56) + 8.(11 + 7)

\[{\rm{ }}\left( { - {\rm{ }}56} \right){\rm{ }} + {\rm{ }}8.\left( {11 + 7} \right)\] \[ = {\rm{ }}\left( { - {\rm{ }}56} \right){\rm{ }} + {\rm{ }}8.11{\rm{ }} + {\rm{ }}8.7\] \[ = {\rm{ }}\left( { - {\rm{ }}56} \right){\rm{ }} + {\rm{ }}88{\rm{ }} + {\rm{ }}56\]

\[ = {\rm{ }}\left[ {\left( { - {\rm{ }}56} \right) + 56} \right]{\rm{ }} + {\rm{ }}88\]\[ = {\rm{ }}88\]