Two possible answers:
2/4 = 3/6 = 9/18
1/4 = 2/8 = 9/36
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Step-by-step explanation:
This type of problem doesn't have any formula or algorithm that I know of. It's just a guess and check type of problem. So far I was able to find two solutions, but other solutions may be possible. Since there are only seven boxes, you'll have two leftover digits that you won't use.