The math node can be useful but it’s not 100% feature-complete. I have no clue why the input pin for CamLerpRate is not showing for you… Maybe right click it an refresh?
If the goal (achieving the ratio you mentioned) was to produce 2 related values, I’d:
The above would play the Timeline with half the speed and the Delay would trigger after 1s, following the aforementioned pattern. And it would work for other values, too; and every other value in between.
Anyway, you can double click the Math Expression node to peek at the nodes it creates. The worst case scenario is that you may need to recreate the equation with 10 or so nodes instead.
And another way to do it, is to create a data curve and sample it:
- the data you mentioned:
- and sampling it:
Hopefully, one of those can get you close.
Good luck!