For the sake of showing work I will replace the empty space with an x like so...

To find out what x is you must cross multiply (aka butterfly)
1*x = 2*6
1x = 12
x = 12
***If you don't understand the "cross multiply" technique let me know in the comments and I'll be happy to explain.
To make these fractions equivalent the empty spot must be 12

Hope this helped!
~Just a girl in love with Shawn Mendes