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| (1)9.9×4.5 =(10-0.1)×4.5 =10×4.5-0.1×4.5 =45-0.45 =44.55 (2)108×1.25 =(100+8)×1.25 =100×1.25+8×1.25 =125+10 =135 (3)14.67×101-14.67 =14.67×(101-1) =14.67×100 =1467 (4)1.25×3.2×25 =1.25×8×0.4×25 =(1.25×8)×(0.4×25) =10×10 =100 (5)0.125×4.8×2.5 =0.125×8×0.6×25 =(0.125×8)×(0.6×25) =1×15 =15 (6)28.7×9.9+2.87 =2.87×(99+1) =2.87×100 =287 |
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