Rounding to 4 decimal places

I haven't tried this, but what if you divide the result by 100? This would mean that you need to multiply the original number by 100 squared, of course.

So, say the learner enters in 16. The final result would, naturally, be 4. You run these steps:
Multiply 16 by 10,000 (160,000)
Take the square root of that number (400)
Divide by 100 (4)

I *think* this may be enough to give you 4 significant digits. If you need more than that, then you could multiply by 1 million and then divide by 1 thousand. I would think that Lectora can handle that kind of calculation, but I'm not entirely sure. 

At the very least, I hope this suggestion inspires you to find the correct solution.

Kevin