(1)0.75×4×0.25×4, =(0.75×4)×(0.25×4), =3×1, =3; (2)9.6+9.9×99, =(9.9-0.3)+9.9×99, =9.9+9.9×99-0.3, =9.9×(1+99)-0.3, =9.9×100-0.3, =990-0.3, =989.7; (3)6.3×10.1, =6.3×(10+0.1), =6.3×10+6.3×0.1, =63+0.63, =63.63; (4)15.58÷8.2-0.72, =1.9-0.72, =1.18; (5)4.536÷0.8÷14, =5.67÷14, =0.405; (6)2.8×3.6+1.4×2.8, =2.8×(3.6+1.4), =2.8×5, =14. |
0.75×4×2.5×4=3×0.25×4×0.25×4=3×1×1=3