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Sealed Solution

Age 7 to 11
Challenge Level

Here is a set of ten cards, each showing one of the digits from 0 to 9:

ten cards showing the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9

The ten cards are divided up between five envelopes so that there are two cards in each envelope.

The sum of the two numbers inside it is written on each envelope:

Five envelopes, each with a number written on it. The numbers are 3, 7, 8, 13 and 14

What numbers could be inside the "8" envelope?

Thank you to Alan Parr who inspired this task.

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