19.在比例尺为$\frac{1}{5000000}$的地图上,量得A、B两地的距离为6厘米,甲、乙两辆汽车分别从两地同时相向开出,经过4小时相遇,甲、乙两车的速度比是7:8,甲汽车每小时行多少千米?
11.直接写出得数.
0 158810 158818 158824 158828 158834 158836 158840 158846 158848 158854 158860 158864 158866 158870 158876 158878 158884 158888 158890 158894 158896 158900 158902 158904 158905 158906 158908 158909 158910 158912 158914 158918 158920 158924 158926 158930 158936 158938 158944 158948 158950 158954 158960 158966 158968 158974 158978 158980 158986 158990 158996 159004 199269
12÷$\frac{1}{2}$= | 1÷0.01= | 9.8÷0.7= | $\frac{5}{6}$×$\frac{6}{7}$×$\frac{3}{5}$= |
$\frac{1}{3}$+$\frac{1}{4}$= | 42×40= | 179+387-287= | 0.5×16×2= |