Respuesta :

401211
It would not make sense if you were to do 
   34 
     28
The right way is 

34
28

Another example is that if you were to subtract by 1 digit by 2

78
  1

This is the wrong one

78
1


kristenwood141
so that you don't subtract the wrong numbers and get the wrong answers. ,
123
-----
386
_____
?