14\5-(2.8-5/7)+2/7怎么简算同3/7-[19/5-(14/5+4/7)]3/5÷[(1/5+1/3)÷2/9]

问题描述:

14\5-(2.8-5/7)+2/7怎么简算
同3/7-[19/5-(14/5+4/7)]
3/5÷[(1/5+1/3)÷2/9]

145-2.8+5/7+2/7=143.2 希望能帮到你!

1、原式=3/7 - [ 19/5 - 14/5 - 4/7]
=3/7 -[1-4/7]
=3/7-1 + 4/7
=1-1
=0
2. =3/5 * 2/9 ÷ ( 1/5+1/3)
=2/15 ÷ 8/15
=2/15 * 15/8
=1/4

14/5-(2.8-5/7)+2/7
=(2.8-2.8)+(5/7+2/7)
=0+1
=1
3/7-[19/5-(14/5+4/7)]
=3/7-(19/5-14/5-4/7)
=(3/7+4/7)-(19/5-14/5)
=1-1
=0
3/5÷[(1/5+1/3)÷2/9]
=3/5÷[8/15÷2/9]
=3/5×15/8×2/9
=1/4