Bài 8 :
A)3/5 x 8/27 x 5/3
= 3/5 x 5/3 x 8/27
= 1 x 8/27
= 8/27
B) 7/19 x 1/3 + 7/19 x 2/3
= 7/19 x ( 1/3 + 7/19 )
= 7/19 x ( 19/57 + 21/57 )
= 7/19 x 40/57
=280/1083
C)365 x 49 - 365 x 39
= 365 x ( 49 -39 )
= 365 x 10
= 3650
D)37 + 64 + 63 + 36
= ( 37 + 63 ) + ( 64 + 36 )
= 100 + 100
= 200
E)456 - 89 - 67
= ( 456 - 67 ) - 89
= 389 - 89
= 300
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