Calcula 9-1= 8-1= 7-2= 6-3= 5-4= 8-4= 5-3= 4-2= 5-1= 5-2= 6-3= 4-4= 5-3= 6-2=
Calcula: 90 - 10 = 80 - 10 = 70 - 20 = 60 - 30 = 50 - 40 = 80 - 40 = 50 - 30 = 40 - 20 = 50 - 10 = 60 - 20 = 60 - 30 = 40 - 40 = 50 - 30 = 60 - 20 =
Calcula: 90 + 1 = 80 + 1 = 70 + 2 = 60 + 3 = 50 + 4 = 40 + 8 = 30 + 5 = 20 + 4 = 10 + 5 = 20 + 5 = 30 + 6 = 40 + 4 = 50 + 3 = 60 + 2 =
Descompone 91 = 81 = 72 = 63 = 54 = 48 = 35 = 24 = 15 = 25 = 36 = 44 = 53 = 62 =
83= 80 + 3