أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
Nowadays, Youtube had become the supporter for almost any tutorial.
Check MS Excel Magic Tricks by Mike Girvin
Like you want to learn for Average & Percentage etc.
Link is https://www.youtube.com/watch?v=c_ZJLJK5PjM
And Worksheets would be available at: