CÁLCULO MENTAL 2.º - NIVEL 9

Calcula mentalmente :
51 + 28 = ____________________
34 + 42 = ____________________
75 + 23 = ____________________
43 + 36 = ____________________

Calcula mentalmente :
67 + 21 = ____________________
52 + 45 = ____________________
14 + 53 = ____________________
46 + 12 = ____________________

Calcula mentalmente :
28 + 61 = ____________________
65 + 24 = ____________________
32 + 57 = ____________________
71 + 21 = ____________________