Fill in the numbers according to the rules and explain the reasons 1,12 ,( ),( ),( ),2 ,1,3

Fill in the numbers according to the rules and explain the reasons 1,12 ,( ),( ),( ),2 ,1,3

1,12 ,( 1 ),( 6 ),( 1 ),2 ,1,3
The odd number is 1, the even number is 12, 6, 2, 3, and the first two numbers are divided to get the third number