64x102一64x2(把128分开)
=64×(102-2)(乘法分配律倒着用丿
=64×100
=6400
64x(100+2)-128=6400+128-128=6400
把102拆成100+2再用64和括号里的数相乘得出6400+128,而128正好被128减去
64x102-128
=64x(100+2)-128
=64x100+64x2-128
=6400+128-128
=6528-128
=6400
64×102-128
=64×100+64×2-128
=6400+128-128
=6400
64×102-128=64×102-64×2=64×(102-2)=64×100=6400