There's a pretty important question of how it did this.

If this model is more along the lines of what DeepMind is doing starting from scratch and building up learnings progressively, then depending on (a) how long it was running, (b) what it was fed, and (c) how long until it is expected to hit diminishing returns, then potentially solving grade school math might be a huge deal or a nothing burger.

The details really matter quite a lot.