This is a fun thought experiment! Here's how to approach it:

1. We need the volumes:

* Mercury's Volume: 6.083 x 10^10 cubic kilometers (km³)

* Moon's Volume: 2.1968 x 10^10 cubic kilometers (km³)

2. Divide Mercury's volume by the Moon's volume:

(6.083 x 10^10 km³) / (2.1968 x 10^10 km³) ≈ 2.77

Therefore, approximately 2.77 Moons would fit inside the planet Mercury.

Important Note: This is a theoretical calculation based on volume. In reality, you can't actually fit objects inside another object like this. This is simply a way to compare their relative sizes.