Question

Your answer should have the same number of significant figures is the start of measurement 400.08mL —— L

Answer 1

The answer would be .40008L

The word milli- translates to $\frac{1}{1000}$ units. In this case, we have liters as our base unit. So a milliliter is $\frac{1}{1000}$ Liters or you can say that there are:

1,000 mL in 1 L. 

As I understand, you are trying to convert 400.08mL to L. 

So this is how you are going to get it:

$400.08mL$ x $\frac{1L}{1,000mL}$
= $\frac{400.08L}{1,000} = 0.40008L$