I marked the pockets in red in the picture. The first goes in the bottom right, the second goes in the top left. And so on.
Explanation:
I think the easiest way is to simplify them all, so that you can find which ones are equal! I marked the pockets in red on each door. But for example, 3/6 is equal to 1/2 because if you multiply 1/2 x 3/3 you get (1 x 3)/ (2 x 3) or 3/6. So the goal is to find a number you can divide the fraction by. You can see if it’s all the way simplified you can no longer divide the top and bottom by the same number. In the second door, you could start by dividing by 2: 4/8 divided by 2/2 is 2/4. But now we can divide by 2 again: 2/4 divided by 2/2 is 1/2. And 1/2 matches one of our pockets, the top left one!