上海玄德实业有限公司:脑算除法第1讲

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脑算除法第1讲


补数除法,有3种;

1、稍小于一百的除补数求商(加除法):从被除数首位起,逐位与除数补数乘加,够一个除数就是补商,保留小数两位。

   补数 043                                 补数01                              补数 03

446919÷957=467                        326÷99=3.29                      453÷97=4.67

+172   4×043                +03    3×01             +12   4×03

464119                       329                     465

 +258   6×043                +02    2×01             +18    6×03

466699                       3292                    4668

  +258    6×043                +09    9×01            +18    6×03

466957                       32929                   46698

  -957 9571                                      97  97

467                                                  46701   

 

2、稍大于一百除补数求商(减除法):从被除数首位起,逐位与除数超补数乘减,不够减退商,保留小数两位。

         补数02                                  补数03

      356÷102=3.49                        782÷103=7.59

     06  3×02                 -21   7×03

      350   不够减5                  761    不够减65

       -08   4×02                -15   5×03   

      3492                       7595

        -18   9×02                -27   9×03

      34902                      75923

 

3、补数求商,加减混合除法:

 补数 212                           补数 21

      788÷198=156024              7189÷79=91

             +424   2×212        +147   7×21

           424   2×212           165   147+18=1582

           156024                 158     2×79  

                                     79    7+29

                                     79     11

                                             91