12.在实数$\sqrt{7}$,6,-$\frac{1}{3}$,2.5中,无理数是( )
| A. | $\sqrt{7}$ | B. | 6 | C. | -$\frac{1}{3}$ | D. | 2.5 |
10.下列计算中,正确的是( )
| A. | a0=1 | B. | $\sqrt{(-3)^{2}}$=-3 | C. | m6÷m2=m3 | D. | 3-2=$\frac{1}{9}$ |
5.下列各数中,最小的数是( )
0 284028 284036 284042 284046 284052 284054 284058 284064 284066 284072 284078 284082 284084 284088 284094 284096 284102 284106 284108 284112 284114 284118 284120 284122 284123 284124 284126 284127 284128 284130 284132 284136 284138 284142 284144 284148 284154 284156 284162 284166 284168 284172 284178 284184 284186 284192 284196 284198 284204 284208 284214 284222 366461
| A. | |-3| | B. | -$\sqrt{3}$ | C. | -$\frac{1}{3}$ | D. | -π |