Đáp án:
Bài 1: Tính hợp lí.
a,`2 2/9: 1 1/9-46/3. 5/23+4/5`
=`20/9 . 9/10-10/3+4/5`
`=2-10/3+4/5`
`=30/15-50/15+12/15`
`=(30-50+12)/15=-8/15`
b,`-5/7 . 2/11+ -5/7 . 9/11+1 5/7`
=`-5/7.(2/11+9/11)+1 +5/7`
=`-5/7 . 1+1+5/7`
`=-5/7 + 1+5/7=1+(5/7-5/7)=1`
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