The modal class of a frequency distribution is $20-24$. Then,in the calculations of mode,$l=$ ..........

$\Sigma(x_{i} - \bar{x}) = \ldots \ldots \ldots$

For a given frequency distribution,$\bar{x}=20, \Sigma f_{i} u_{i}=-50, n=100$ and $c=10$. Then,assumed mean $A = \ldots \ldots \ldots \ldots$

$\frac{Z-M}{M-\bar{x}}=\ldots \ldots \ldots \ldots$

In a frequency distribution with total frequency $48$,$\bar{x}=70$,$\Sigma f_{i}=43+f$,and $A=66$. Then,the missing frequency $f=$ .........

If $Z - M = 4$,then $M - \bar{x} = \dots$