Estrategias de suma.

Aquí les dejo las estrategias que empleamos para sumar y restar sin utilizar la grilla numérica.

23+15=

            23                                      +                                      15=

10+10+1+1+1                               +                  10+1+1+1+1+1=

10+10+10                                     +           1+1+1+1+1+1+1+1=

30                                                  +                       8                 = 38

           23                                       +                                      15=

20 + 3                                            +                   10+5               =

20+10                                            +                    3+5                =

30                                                  +                      8                  = 38