计算,能简算的要简算.3.2×1.8+2.54198×0.511.25×32×2.50.8×72.4×12.55.2×10.12.5×3.7+6.3×2.5.
(1)3.2×1.8+2.54, =5.76+2.54, =8.3; (2)198×0.51, =(200-2)×0.51, =200×0.51-2×0.51, =102-1.02, =100.98; (3)1.25×32×2.5, =1.25×(4×8)×2.5, =(1.25×8)×(4×2.5), =10×10, =100; (4)0.8×72.4×12.5, =0.8×12.5×72.4, =10×72.4, =724; (5)5.2×10.1, =5.2×(10+0.1), =5.2×10+5.2×0.1, =52+0.52, =52.52; (6)2.5×3.7+6.3×2.5, =2.5×(3.7+6.3), =2.5×10, =25. |
计算,能简算的要简算.3.2×1.8+2.54198×0.511.
(1)3.2×1.8+2.54,=5.76+2.54,=8.3;(2)198×0.51,=(200-2)×0.51,=200×0.51-2×0.51,=102-1.02,=100.98;(3)1.25×32×2.5,=1.25×(4×8)×2.5,=(1.25×8)×(4×2.5),=10×10,=100;(4)0.8×72.4×12.5,=0.8×12.5×...