Question

7/21 added by ------------ = 12/21

Answer 1

Answer:

12/21-7/21

= (12-7)/21

= 5/21......

Answer 2

Answer:

7/21 + ___________=12/21

Let the number that should be added to 7/21 to get 12/21 be x

7/21 + x = 12/21

x= 12/21-7/21

x=5/21

So 7/21+ 5/21=12/21