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沪科版七年级上册数学书习题1.5答案

时间:2016-07-25 来源:书通网 共计7题

习题1.5第1题答案

(1)-10

(2)0

(3)-1/250000

(4)-64/9 

习题1.5第2题答案

(1)(-3)×(-4)×(-5)

=-3×4×5

=-60

(2)(-7/8)×15×(-8/7)

=7/8×15×8/7

=(7/8×8/7)×15

=1×15

=15

习题1.5第3题答案

(1)(-1)×(2-5)

=(-1)×2+(-1)×(-5)

=-2+5

=3

(2)8-3×(4-6)=8-3×(-2)

=8+3×2

=14

(3)(-3/4)×(-8+2/3-4/3)

=-[3/4×(-8)+3/4×2/3-3/4×4/3]

=-(-7+1/2)

=-(-6 1/2)

=61/2

(4)(-1.2)×(-5/8)+(-24)×1/12

=1.2×5/8+(-2)

=6/5×5/8-2

=3/4-2

=-1又1/4 

习题1.5第4题答案

(1)原式=4/3×4/3=16/9 

(2)原式=3/5×5/3=1     

(3)原式=-1.84×2=-3.68       

(4)原式=1/4×1/4=1/16              

(5)原式=0  

(6)原式=-3/4×8/45=-2/15

习题1.5第5题答案

(1)-6÷(-0.25)×5/6

=6÷0.25×5/6

=6×4×5/6

=20

(2)(-17)×(-9)×0×37=0

(3)(-60)×(3/4)+5/6-11/15-7/12)

=-(60×3/4+60×5/6-60×11/15-60×7/12)

= -(45+50-44-35)

=-16

(4)-9×(-11)-12×(-8)=99-(-96)

=99+96

=195 

习题1.5第6题答案

(1)原式=1-1/5×(-3-4×18/5+4×53/10)

=1-1/5×(-3-72/5+106/5)

=1-1/5×(-15/5-72/5+106/5)

=1-1/5×19/5

=6/25

(2)原式(1/20-15/20)×(10/14-5/14)

=-14/20×5/14

=-1/4

(3)原式=-22/7×(22/7-4/3)×7/22÷(-22/21)

=22/7×38/21×7/22×21/22

=19/(11)

(4)原式=[4-(12+12-40)]÷5=20÷5=4  

习题1.5第7题答案

(1)6

(2)-6

(3)-1/5

(4)-5

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