Question

resuelvo las siguientes sustracciones
b) 20 sobre 21 - 17 sobre 30 - 4 sobre 15 =

Answer 1

20/21 - 17/30 - 4/15 =                                 21      30      15     2
200/210 - 119/210 - 56/210 =                     21      15       15    3
200/210 - 175/210 =                                     7        5         5    5
25/210 = 5/42                                               7        1         1    7
                                                                     1        1         1
                                                                    2 X 3 X 5 X 7 = 210