乘法分配律为:两个数的和与一个数相乘,先将它们与这个数分别相乘,再相加,积不变.即:(a+b)×c=a×c+b×c.反过来则:a×c+b×c=(a+b)×c32×21+32×78+32= 32× ( 21+78+1)= 32×100=3200
32×21+32×78+32=32×(21+78+1)=32×(22+78)=32×100=3200
32×21+32×78+32=32×(21+78+1)=32×100=3200