1.提示:(1)-10 . (2)0 . (3)-1/250000 . (4)-64/9 .
2.解:(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 .
3.解:(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 1/4 .
4.解:(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 .
5.解:(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 .
6.解:(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 .
7.(1)6 (2)-6 (3)-1/5 (4)-5