Видео с ютуба Maths Tricks And Tips

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

Mental Addition and Subtraction Tips — Math Tricks with Arthur Benjamin

5 простых математических приёмов для быстрых вычислений | Математические приёмы на каждый день | ...

10 Math Tricks School Didn't Teach You But Should Have

Square any 2 digit number in 3 seconds I Crazy Math Trick