19.得数大于$\frac{7}{12}$的算式是( )
| A. | $\frac{7}{12}$÷$\frac{3}{2}$ | B. | $\frac{7}{12}$×$\frac{2}{3}$ | C. | $\frac{7}{12}$×$\frac{7}{12}$ | D. | $\frac{7}{12}$÷$\frac{2}{3}$ |
18.下列各组数中,互为倒数的是( )
| A. | $\frac{3}{4}$和$\frac{1}{4}$ | B. | 0.125和8 | C. | $\frac{3}{8}$和0.375 | D. | $\frac{6}{5}$和$\frac{1}{5}$ |
17.若2:3的前项增加6,要使比值不变,后项要( )
| A. | 增加6 | B. | 增加6倍 | C. | 扩大3倍 | D. | 增加9 |
16.把甲班人数的$\frac{1}{5}$调查给乙班,两班人数相等,原来乙班人数是甲班的( )
| A. | $\frac{1}{5}$ | B. | $\frac{2}{5}$ | C. | $\frac{3}{5}$ | D. | $\frac{4}{5}$ |
15.把一根绳子剪成甲、乙两段,甲段是全长的$\frac{5}{8}$,乙段长$\frac{7}{8}$米,甲乙两段相比,则( )
0 133637 133645 133651 133655 133661 133663 133667 133673 133675 133681 133687 133691 133693 133697 133703 133705 133711 133715 133717 133721 133723 133727 133729 133731 133732 133733 133735 133736 133737 133739 133741 133745 133747 133751 133753 133757 133763 133765 133771 133775 133777 133781 133787 133793 133795 133801 133805 133807 133813 133817 133823 133831 199269
| A. | 甲段长 | B. | 乙段长 | C. | 一样长 | D. | 无法确定 |