loved it. thanks.
I would like a “deep” math lesson that demonstrated to me WHY this little “trick” works. That - even more “nerdy”, yes, would be very interesting as well.
Ping me when you do.
I will do the same if I perchance do.;-)
This can be done graphically or with algebra.
A is the number you want to square
d is the difference between the number and 100
2’s are super script meaning square, i don’t know how to format it that way
A=100-d
A2=(100-d)2
= 10000 -200d+d2
Given 100(A=100-d)
100A=10000-100d
Substitute for 10000 and simplify
= 100A-100d+d2
A2= 100(A-d)+d2
I don’t know how to add an image so I can’t show it graphically.
The problem with the fast method is that he did not explain why it works and leaves the person a cripple. What is 98 squared? By his method it is 964 which is wrong, it is 9604. What is 783 squared. It can be done if you understand what is going on with the method. By it more like grammer class. many many rules with exceptions for each rule. Learn how to do math right and understand why the short cuts work.
If someone can tell mehow to post a graphic i will show it because it is very understandable that way.