In the following problems, you are asked to convert from one number base to another, you must show all your work.

1. Convert the 8-binary binary expansion (1100 1010)2 to a decimal expansion.

2. Convert the following decimal expansion (145)10 to an 8-bit binary expansion.

3. Convert the following hexadecimal expansion (BA3)16 to an octal expansion. 

4. Convert the following binary expansion (1010 0101 0110 0101)2 to a hexadecimal expansion.