Đề bài: Tính nhanh
a, (-4) x 123 x (-125) x (-11) x (-8)
b, (-823) x (1-812) - 812 x 823
c, (-47) x 101
d, 12 + (-47) x 12 - 6 (-12)
e, 32 x (132 - 247) - 132 x (32 - 247)
g, (-45) x (-16) x (-125) x (-1)^2018
a, [tex](-4) . 123 . (-125) . (-11) . (-8)\\\\ =4.123.125.11.8\\\\ =(125.8).(4.120+4.3).11\\\\ =1000.(480+12).11\\\\ =1000.492.11=1000.(4920+492)=1000.5412=5412000[/tex]
b, [tex](-823) . (1-812) - 812 . 823\\\\ =823.(812-1)-812.823\\\\ =823.812-823-812.823=-823[/tex]
c, [tex](-47) . 101=(-47).100-47=-4700-47=-4747[/tex]
d, [tex]12 + (-47) . 12 - 6 (-12)\\\\ =12+12.(-47)+6.12\\\\ =12.(1-47+6)=12.(-40)=-480[/tex]
e,[tex]32 . (132 - 247) - 132 . (32 - 247)\\\\ =32.132-32.247-132.32+132.247\\\\ =247.(132-32)=247.100=24700[/tex]
g, [tex](-45) . (-16) . (-125) . (-1)^{2018}\\\\ =(-45).4.4.125.1\\\\ =500.(-180)=-90000[/tex]