Direction : What value should come in place question mark(?) in the following questions?

0.75 % of 90 + 0.55 % of 80=?

What mathematical operation should come at the place of ‘?’ in the equation:
2 ? 6 – 12 ÷ 4 +2 =11.

1-[5-{2+(-5+6-2)2}] is equal to 

$$\sqrt{x}÷ \sqrt{144} = 0.02, $$ then the value of x is 

The smallest natural number, by which 3000 must be divided to make the quotient a perfect cube, is : 

$$ { \sqrt{(0.798)^2+0.404×0.798+(0.202)^2}+1=?} $$

If $$ {3\sqrt{{1-a}\over{a}}}+9={19-3\sqrt{{a}\over{1-a}}}$$, then what is the value of a?

Direction: what should come in place at question mark(?).

$$ {4\over 7}×{2{4\over 5}÷{2\over 5}=?}$$