Query about "Risk and uncertainty (part 2) – ACCA (AFM) lectures"

Hi sir. Thank you for the great lecture. Please may I ask, in the exam, if I straightaway multiply by 1.645 (for 95% confidence) or 2.33 (for 99% confidence) without showing how to get that figures (by deducting that 50% to derive it from the normal distribution table), will I still earn the marks? Thank you. :)