4:2

The expression "4:2" can be interpreted in a couple of different ways, depending on the context:

1. Ratio: It can represent the ratio of 4 to 2, which simplifies to 2:1.
2. Division: As a division operation, it would equal 2, since 4 divided by 2 is 2.

If this is related to a specific topic or context in your exam preparation, please provide more details!