Introduction to numbers

Q.

The binary number system has a base of?

Q.

Write the following expanded forms in the standard form

$9,00,000+5,000+200+80$

Q.

What is the value of the given expression?
$\left[\right[3\times \left\{\right(-5)\times (-4\left)\right\}]÷\{27+(-13-4\left)\right\}]$
$+[\{27\times (-2\left)\right\}÷(-3-3\left)\right]$
$+[\left\{\right(-3)\times (-3)\times 5\}÷(-3\left)\right]]$

1. $0$

2. $1$

3. $-1$

4. $13$