How many ways are there to split a group of 4 students…

How many ways are there to split a group of 4 students into two groups of 2 students each? (The order of the groups does not matter)

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 #19261