(1)4.63×1.4+46.3×0.86 =46.3×0.14+46.3×0.86 =46.3×(0.14+0.86) =46.3×1 =46.3 (2)125×3.2×2.5 =125×8×0.4×2.5 =(125×8)×(0.4×2.5) =1000×1 =1000 (3)0.9+9.9+99.9+999.9 =1﹣0.1+10﹣0.1+100﹣0.1+1000﹣0.1 =(1+10+100+1000)﹣(0.1+0.1+0.1+0.1) =1111﹣0.4 =1110.6 (4)25×11.2×4 =25×4×11.2 =100×11.2 =1120 (5)23.25﹣6.75﹣3.25 =23.25﹣(6.75+3.25) =23.25﹣10 =13.25