475x99=475x(100-1)=47500-475=47025
乘法分配律 ab+ac=ax(b+c) a(b-c)=ab-ac
25x125x4x8=(25x4)x(125x8)=100x1000=100000
乘法交换律:axb=bxa 乘法结合律:axbxc=ax(bxc)
475×99
=475×100-475
=4750-475
=4275
25×125×4×8
=(25×4)×(125×8)
=100×1000
=100000
475乘(100-1)
475x100-475=47025
25x4x(125x8)=100000
25×4,125×8,或者25×8,125×4