Question

格式 分子/分母1、计算2.5×13-3×2.5 4/9÷(7/9+4/9)×3/4 5/13×4/7×14 1/10×

Answer 1

1、2.5×13-3×2.5=2.5×(13-3)=2.5×10=25
4/9÷(7/9+4/9)×3/4=4/9÷(7/9×3/4+4/9×3/4)=4/9÷(7/12+1/3)=4/9÷11/12=16/33
5/13×4/7×14=40/13
1/10×(1/3+1/3×9 ) =1/10×(1/3+3)=1/10×10/3=1/3
9/20÷[2/1×(2/3+0.8）] =9/20÷[2/1×(2/3+4/5)]=9/20×(2/3+4/5)=9/20×2/3+9/20×4/5=3/10+9/25=33/50
4/9×5×18 =40
2 5X-20=25×0.4
5x-20=10
5x=30
x=6
5.4X-0.25×8=3.4
5.4x-2=3.4
5.4x=5.4
x=1
x-2/5x=14
3/5x=14
x=70/3
3、
20×15+(20+15)×8×2-120
=300+560-120
=860-120
=740（平方米）
740×0.5=370(千克)
共用涂料370千克.