a) 27,42 + 51,24 + 22,58 - 28,76
= 51,24 + 28,76 - 27,42 + 22,58
= 80 - 50
= 30
b) 28,67 x 99 + 28,67
= 28,67 x 99 + 28,67 x 1
= 28,67 x ( 99 + 1 )
= 28,67 x 100
= 2867
^ - ^
a,27,42+51,24+22,58-48,76
=(27,42+22,58)+(51,24-48,76)
=50+2,48
=52,48
b,28,67x99+28,67
=28,67x99+28,67x1
=28,67x(99+1)
=28,67x100
=2867
P/s : học vui^^a) 27,42+51,24+22,58-28,76
=27,42+22,58-51,24+28,76
=50+80=130
b) 28,67x99+28,67
=28,67x99+28,67x1
=28,67x(99+1)
=28,67x100=2867
a, 27,42 + 51,24 + 22,58 - 28,76
= ( 51,24 + 28,76 ) - ( 27,42 + 22,58 )
= 70 - 50
= 20
b, 28,67 x 99 + 28,67
= 28,67 x 99 + 28,67 x 1
= 28,67 x ( 99 + 1 )
= 28,67 x 100
= 2867