4.若a>b,则下列式子正确的是( )
| A. | a-4>b-3 | B. | $\frac{1}{2}$a<$\frac{1}{2}$b | C. | -3a>-3b | D. | 3+2a>3+2b |
2.下列各式计算正确的是( )
0 278915 278923 278929 278933 278939 278941 278945 278951 278953 278959 278965 278969 278971 278975 278981 278983 278989 278993 278995 278999 279001 279005 279007 279009 279010 279011 279013 279014 279015 279017 279019 279023 279025 279029 279031 279035 279041 279043 279049 279053 279055 279059 279065 279071 279073 279079 279083 279085 279091 279095 279101 279109 366461
| A. | $8\sqrt{3}-2\sqrt{3}=6$ | B. | $5\sqrt{3}+5\sqrt{2}=10\sqrt{5}$ | C. | $4\sqrt{3}×2\sqrt{2}=8\sqrt{6}$ | D. | $4\sqrt{2}÷2\sqrt{2}=2\sqrt{2}$ |