8 8 8 8=8

One clean solution using four 8s:

• sqrt(8) * sqrt(8) + sqrt(8) - sqrt(8) = 8

Explanation: sqrt(8) * sqrt(8) = 8, and the + sqrt(8) - sqrt(8) cancels out, leaving 8. This uses exactly four 8s.

Would you like more solutions (e.g., allowing factorial, powers, decimals, etc.)?