16:06

yes, !! is also a math symbol

12:46

6 Impossible Puzzles With Surprising Solutions

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FOIL is Stupid and Silly

9:44

Kaprekar's Constant

31:34

How Good Are Your Eyes?

3:57

How to Calculate faster than a Calculator? | Mental Maths | (Part -1, 47 × 25 in a second)| #howto

7:20

How to Calculate Faster than a Calculator - Mental Math #1

12:26

Une façon insensée d’ouvrir n’importe quelle serrure sans clé ! Astuces étonnantes