练习十1.乘法结合律 乘法交换律和结合律 乘法分配律2.√ x √x3.=18x(200+1) =18x200+18 =3600+18 =3618 =125x8+125x20=1000+2500=3500 =15x2x27=30x27=810 =76x(100-1)=76x100-76=7600-76=7524=27x(38+62)=27x100 =2700=84x(99+1)=84x100 =84004.=45x(20-2)=45x20-45x2=900-90=810 =71x(100+1)=71x100+71=7100+71=7171=29x(4x5)=29x20 =580 =25x4x9=100x9=900 =35x(10+2)=35x10+35x2=350+70=420 =6x5x17=30x17=5105.(1)480 480 相等 (2)5544 5544 相等6.=7x(256- |