- #1
phoenixy
Hi,
I'm trying to get my 8 years old cousin into math. I taught him a couple math tricks that he can workout in his head, so that he can impresses his classmates and teacher(in "I can do this in my head faster than you with a calculator" kind of way).
Here the ones that I had off the top of my head:
11*XY = X (X+Y) Y; 11*45 = 4 (4+5) 5 = 495
(X5)^2 = (X*(X+1)) 25; 75^2 = 7*8 25 = 5625
Anybody knows any similar number games that can be done using only your head?
I'm trying to get my 8 years old cousin into math. I taught him a couple math tricks that he can workout in his head, so that he can impresses his classmates and teacher(in "I can do this in my head faster than you with a calculator" kind of way).
Here the ones that I had off the top of my head:
11*XY = X (X+Y) Y; 11*45 = 4 (4+5) 5 = 495
(X5)^2 = (X*(X+1)) 25; 75^2 = 7*8 25 = 5625
Anybody knows any similar number games that can be done using only your head?