\[\sum_{n=1}^{7} 2(-2)^{n-1}\]
Http://ncalculators.com/matrix/4x4-matrix-multiplication-calculator.htm
you would have 32 multiplication and 16 addition I believe because.
2 2x2 matrices Is 8 multiplication and 4 addition
2.5
If you add and divide do one it helps
The bigger decimal is 0.20