The average of seven numbers is 4

The average of seven numbers is 4. The average of first three numbers is 2 and the average of last three numbers is 6. What is the middle number?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #32784