How many digits will be there in the cube root of $512$?

What will come at the place of the question mark(?) 

$75$ of $\frac{1}{30}÷\frac{1}{2}=?$

If $‘÷’$ denotes $‘+’$ and $‘-’$denotes $‘\times ’$, then find the value of $\left(\right(7÷0.5) –2) –5.$

$84÷\left[-5+\left(-4\right)of\left\{32÷\left(-16÷-2\right)\right\}\right]=?$

If $\text{'}+\text{'}$ represents $‘\times ’$, $‘\times ’$ represents$‘–’$,$‘÷’$ represents $‘+’$ and $‘–‘$ represents $‘÷’$ then find the value of

$100-25÷7+30\times 2+9$

Find the difference between $0.02$ and $0.002$

Simplify:

$\left(77+14\right)-\frac{42}{7}\times 3+\left(12-9\right)$=?

Simplify:

$100\times 10-100+2000÷100=?$