Ok, I'm confused.

The rate of gravitational acceleration is 9.8 m/s2

Now, when it's expressed as 9.8 m/s/s - I get that, the rate increases 9.8m per second, every second. Hence;

0s = 0
1s = 9.8m
2s = 19.6m
3s = 29.4m
4s = 39.2m

That all makes sense to me. However, when expressed as 9.8 m/s2 - I don't understand the squaring bit = how does that work in terms of the calculation?