To convert the binary number $1011011_2$ to a Hindu-Arabic (decimal) number, we follow these steps:

Each digit in the binary number represents a power of 2, starting from the rightmost digit (which is the $2^0$ place).

1. $1 \times 2^6 = 64$
2. $0 \times 2^5 = 0$
3. $1 \times 2^4 = 16$
4. $1 \times 2^3 = 8$
5. $0 \times 2^2 = 0$
6. $1 \times 2^1 = 2$
7. $1 \times 2^0 = 1$

Now, sum them up: $64 + 16 + 8 + 2 + 1 = 91$

So, the binary number $1011011_2$ is equivalent to $91$ in the Hindu-Arabic (decimal) system.

Would you like more details on binary-to-decimal conversion, or do you have any other questions?

Here are 5 related questions:

1. How do you convert a decimal number to binary?
2. What is the binary equivalent of 156 in decimal?
3. How is hexadecimal conversion related to binary?
4. What is the binary representation of negative numbers in two's complement?
5. How do binary numbers work in computing systems?

Tip: When converting from binary to decimal, remember that the rightmost digit always represents $2^0$, and you increase the exponent by 1 as you move to the left.