Algebra för Ma1A

Tankegympa

Från Quora:

Wu's Squaring Trick, named after the famous Scott Wu, is a technique used to quickly square numbers over 25 in your head. It uses the identity

n² = (n-25) \cdot 100 + (n-50)²

For example,

[math]\displaystyle{ 62^2 = 37 \cdot 100 + 12^2 = 3844 }[/math]

44^2 = 19 \cdot 100 + 6^2 = 1936

77^2 = 52 \cdot 100 + 27^2 = 5929

These mental computations can be done very quickly with just a little practice, so amaze your friends with how fast you can square two digit numbers!