why minus x minus = positive
https://www.youtube.com/watch?v=WgWv9ftYO9c
Multiply Numbers And Algebra Equations By Drawing Lineshttps://www.youtube.com/watch?v=0SZw8jpfAk0
Mathemagician https://www.youtube.com/watch?v=e4PTvXtz4GM
understanding quadratic equation https://www.youtube.com/watch?v=EBbtoFMJvFc
Balancing linear equations through an activity ; easiest method!
https://www.youtube.com/watch?v=ijVnb0EVA8M
Vedic Maths - cube roots in just 2 seconds!
https://www.youtube.com/watch?time_continue=8&v=gIo88Rt1JtI
Vedic Maths - Find the DAY of the week in less than 30 seconds
https://www.youtube.com/watch?v=Ig3m365yJws
More tricks
http://www.inno-teach.com/videos.html
https://www.youtube.com/watch?v=-wkr_vf18cw
Biomath - good
http://www.biology.arizona.edu/biomath/BioMath.html
Dont Memorise math
https://www.youtube.com/watch?v=_-x90wGBD8U
Teaching math without home wok
http://www.leadinggreatlearning.com/teaching-math-without-homework/
why negative number multiplied by negative is positive
http://mathforum.org/dr.math/faq/faq.negxneg.html
https://www.khanacademy.org/math/arithmetic/arith-review-negative-numbers/arith-review-mult-divide-negatives/v/why-a-negative-times-a-negative-is-a-positive
Math and games