Đề bài : tính nhanh Giúp mình với Question Đề bài : tính nhanh Giúp mình với in progress 0 Môn Toán Sigridomena 10 months 2021-04-20T20:02:02+00:00 2021-04-20T20:02:02+00:00 2 Answers 21 views 0
Answers ( )
1)
`7/13 – 4/5 + 9/5 -33/13`
`= (7/13 -33/13) + ( -4/5 + 9/5 )`
`= -2+ 1`
`=-1`
2)
`4 4/9 -( 2 2/7 + 3 4/9)`
`= 4 4/9 – 2 2/7 – 3 4/9`
`= 1 – 2 2/7`
`= 1 -16/7`
`=-9/7`
3)
`360 . (13/180 – 7/120 + 1/450)`
`= (360.13)/180 – (360.7)/120 + 360/450`
`= 2. 13 – 3.7 +4/5`
`= 26 – 21 + 4/5`
`=5 + 4/5`
`=29/5`
4)
`-5/11 . 4/17 + 2/33 + (-4/17) . 12/11`
`= -5/11 . 4/17 + 2/33 + 4/17 . (-12/11)`
`= 4/17[(-5/11) + (-12/11)] + 2/33`
`=4/17 .(-17/11) + 2/33`
`= -4/11 + 2/33`
`= -10/33`
5)
`(-45/7 : 13/23 + (-45/7) . 3/13) : 45`
`= ( -45/7 . 23/13 + (-45/7) . 3/13) :45`
`= -45/7(23/13 + 3/13) : 45`
`= -45/7 . 2 . 1/45`
`=-2/7`
6)
`13/15 (15/13 -2) – 8/45 .( 45+ 3/2)`
`= 13/15 . 15/13 – 2 . 13/15 – 8/45 . 45 – 8/45 . 3/2`
`= 1- 26/15 -8 -4/15`
`= -7 – 2`
`=-9`
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