정보 제곱 암산 초스피드

https://www.youtube.com/watch?v=TSwOlerqvIE

합차쓰기 애매한 두자리수, 세자리수

https://www.youtube.com/watch?v=cmRmYzjYFR8

빠른 루트 암산 (ft. 완전제곱인걸 알 때)

https://www.youtube.com/watch?v=umX6af1TLJg

[중1] 음수의 거듭제곱 개념, 거듭제곱 계산 방법 / 정수와 유리수 (13강)

https://www.youtube.com/watch?v=xDZ7pHmHnfc

세 줄씩 쓰던 곱셈은 이제 그만.

https://www.youtube.com/watch?v=QG8KpllJFQQ

a^2=(a-b)*(a+b)+b^2 - Wolfram|Alpha

https://www.wolframalpha.com/input?i=a%5E2%3D%28a-b%29*%28a%2Bb%29%2Bb%5E2

a*(a-c)=((a-b)*(a+ b) +b^2)-(a*c) - Wolfram|Alpha

https://www.wolframalpha.com/input?i=a*%28a-c%29%3D%28%28a-b%29*%28a%2B+b%29+%2Bb%5E2%29-%28a*c%29