Tính nhanh

1. Tính nhanh :
a) 8/9 : 2/3 - 1/3 : 2/3 =.........................................................................................................................................................................
=..........................................................................................................................................................................
b) 9/10 x 3/4 - 1/2 x 3/4
=.........................................................................................................................................................................
=.........................................................................................................................................................................
c) 15/7 : 1/2 = 3/14 : 1/2
=..........................................................................................................................................................................
=.............................................................................................................................................................................
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