17.349×25×4=349×(25×4)这是根据( )
| A. | 乘法交换律 | B. | 乘法结合律 | ||
| C. | 乘法交换律和乘法结合律 |
16.把9.0549保留两位小数后的数是 ( )
| A. | 9.06 | B. | 9.05 | C. | 9.10 |
14.脱式计算,能简算的要简算.
| 0.8×6.3-0.8×3.8 | 0.125×32×2.5 | 0.74×0.99 |
| 0.78÷3.9×4.2 | 8.46-2.46÷6 | (20-0.8×9)×5.7 |
12.直接写出计算结果
0 127942 127950 127956 127960 127966 127968 127972 127978 127980 127986 127992 127996 127998 128002 128008 128010 128016 128020 128022 128026 128028 128032 128034 128036 128037 128038 128040 128041 128042 128044 128046 128050 128052 128056 128058 128062 128068 128070 128076 128080 128082 128086 128092 128098 128100 128106 128110 128112 128118 128122 128128 128136 199269
| 40÷0.5= | 3.2÷0.2= | 72÷0.8= | 32.8÷4= |
| 2.5×0.4= | 4.8×2= | 0.6×1.5= | 9.1÷13= |
| 2.14÷0.4= | 0.99+0.1= | 42×0.01= | 4×1.25= |