Respuesta :

lets say that you have 4-2=? you can use a bar model.... 

 {the stars are the bars}
 you have 4 total and now you need to subtract 2
****
{ i just took away 2 and then you count the bars but in this model count the stars}
**

Hope this helps!!! 

It can be used because it shows how many of something you took away .