① 1/3×1/15+1/3×1/5 ② 3/4-5/8×3/4 ③ 14/25÷(1/5+1/2) ④ [ 3/4-(7/16-0.25)]×17/9
解:① 1/3×1/15+1/3×1/5
=1/3×﹙1/15+1/5﹚
=1/3×4/15
=4/45
② 3/4-5/8×3/4
=3/4×﹙1-5/8﹚
=3/4×3/8
=9/32
③ 14/25÷(1/5+1/2)
=14/25×10/7
=4/5
④ [ 3/4-(7/16-0.25)]×17/9
=[3/4-7/16+1/4]×17/9
=[1-7/16]×17/9
=9/16×17/9
=16/17.
=追问
=1/3×﹙1/15+1/5﹚
=1/3×4/15
=4/45
② 3/4-5/8×3/4
=3/4×﹙1-5/8﹚
=3/4×3/8
=9/32
③ 14/25÷(1/5+1/2)
=14/25×10/7
=4/5
④ [ 3/4-(7/16-0.25)]×17/9
=[3/4-7/16+1/4]×17/9
=[1-7/16]×17/9
=9/16×17/9
=16/17.
=追问
最后一题是17/16吧
追答是的。对不起,我打错了。
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第1个回答 2013-12-17
1、1/3×(1/15+1/5)=1/3×4/15=4/45
2、3/4×(1-5/8)=3/4×3/8=9/32
4、[ 3/4-(7/16-0.25)]×17/9=[ 3/4-7/16+0.25)]×17/9=9/16×17/9=17/16
③ 14/25÷(1/5+1/2)=14/25÷(2/10+5/10)=14/25÷7/10=14/25×10/7=4/5
0
2、3/4×(1-5/8)=3/4×3/8=9/32
4、[ 3/4-(7/16-0.25)]×17/9=[ 3/4-7/16+0.25)]×17/9=9/16×17/9=17/16
③ 14/25÷(1/5+1/2)=14/25÷(2/10+5/10)=14/25÷7/10=14/25×10/7=4/5
0
第2个回答 2013-12-17
1、 1/3(1/15+1/5)=1/3*4/15=4/45
2、 3/4(1-5/8)=3/4*3/8=9/32
3、 14/25÷7/10=14/25*10/7=4/5
4、 (3/4-7/16+1/4)*17/9=9/16*17/9=17/16
2、 3/4(1-5/8)=3/4*3/8=9/32
3、 14/25÷7/10=14/25*10/7=4/5
4、 (3/4-7/16+1/4)*17/9=9/16*17/9=17/16
第3个回答 2013-12-17
①222/7965 ②9/32 ③4/5 ④17/16