17.小虎做了以下4道计算题:①0-(-1)=1;②$\frac{1}{2}÷({-\frac{1}{2}})=-1$;③$-\frac{1}{2}+\frac{1}{3}=-\frac{1}{6}$;④(-1)2015=-2015,请你帮他检查一下,他一共做对了( )
| A. | 1题 | B. | 2题 | C. | 3题 | D. | 4题 |
16.据有关资料显示,2014年末,盐城全市户籍人口828.5万人,将828.5万用科学记数法可表示为( )
0 309771 309779 309785 309789 309795 309797 309801 309807 309809 309815 309821 309825 309827 309831 309837 309839 309845 309849 309851 309855 309857 309861 309863 309865 309866 309867 309869 309870 309871 309873 309875 309879 309881 309885 309887 309891 309897 309899 309905 309909 309911 309915 309921 309927 309929 309935 309939 309941 309947 309951 309957 309965 366461
| A. | 8.285×103 | B. | 828.5×104 | C. | 8.285×105 | D. | 8.285×106 |