138 x 42 + 27 x 45 - 42 x 38 + 27 x 55
= 42 x ( 138 - 38 ) + 27 x ( 45 + 55 )
= 42 x 100 + 27 x 100
= 4200 + 2700
= 6900
Học tốt
138 x 42 + 27 x 45 - 42 x 38 + 27 x55
=138 x 42 - 42 x 38+ 27 x 45+ 27 x55
=42x(138-38)+27x(45+55)
=42x100+27x100
=4200+2700=6900
138 x 42 + 27 x 45 - 42 x 38 + 27 x 55
= 42 x ( 138 - 38 ) + 27 x ( 45 + 55 )
= 42 x 100 + 27 x 100
= 4200 + 2700
= 6900