Chemistry question help?

Question

A chemist adds 0.15L of a 0.172 mol/L potassium permanganate solution (KMnO4) to a reaction flask. Calculate the millimoles of potassium permanganate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

??? = mmol

Answer 1

You do something and something else. Boom 💥 

Answer 2

Using Unit Cancellation (Dimensional Analysis or Unit Factor) method:

0.15 L (0.127 mol/1 L) (1000mmol/1 mol) = 19.05mmol

Now round to 2 sigfigs (since 0.15 has only 2): 19. mmol