脱式计算,能简算的要简算: 4.67-(2.98+0.67); | ÷[-(+)]; | 8×0.4×12.5×2.5; |
125×(8+0.8+0.08); | 1.89×0.9+0.189; | 23.8×99+2.38. |
估算.
68×102≈ | 396×41≈ | 92×28≈ | 198×21≈ |
直接写得数.
14×20= | 2×= | 1+-= | ( +)×9= |
72÷= | 1.5×100= | 1.25×8= | 99×0.8+0.8= |
3.14×20= | 2×= | 1+-= | ( +)×9= |
72÷= | 1.5×100= | 1.25×8= | 99×0.8+0.8= |