# How to convert these numbers?

I am trying to understand number systems: (binary and decimal)

How can I convert the following numbers using the least amount of digits:

1. $(47)\text{base}-10$ to signed binary.

2. $(-27)\text{base}-10$ to signed and binary magnitude

3. $(213)\text{base}-16$ to a 10 base number

Here are my try:

1. $00101111$

2. $10011011$ (or 2's complement: $11100101$)

3. $531$