Multiplication by short cut methods

Find the mean deviation by short cut method.

Find the mean for the following distribution table by short cut method:

Method to calculate Mean by short-cut method

Find the mean and standard deviation using short cut method

Find the mean and standard deviation using short cut method

calculate standard Deviation by the short-cut Method.

Discussion OF ex-3.4,|| Cross-multiplication method || Short method to remembering cross-multiplication method by Determinant || Example-14,15