by DEISY MABEL GUERRERO ARIZA 10 years ago
4895
More like this
by Daniela ardila
by Carranza Maza Jacqueline
by Loor Santana Mario Xavier
by tania alvarez
a + 0 = a b + 0 = b c + 0 = c
a + b = c y b+ a = c
(a + b) + c = a + (b + c)