A good answer might be:

0110   =  610 
0111   =  710 
----     ---
1101   = 1310

A Longer Example

Here is another example: 

                      0           10
  0110 1110    0110 1110    0110 1110
+ 0001 0111    0001 0111    0001 0111
  ---------    ---------    ---------
                       1           01

       110        1 110       11 110
  0110 1110    0110 1110    0110 1110
  0001 0111    0001 0111    0001 0111
  ---------    ---------    ---------
        101         0101       0 0101

   111 110     1111 110    01111 110
  0110 1110    0110 1110    0110 1110
  0001 0111    0001 0111    0001 0111
  ---------    ---------    ---------
    00 0101     000 0101    1000 0101
The carry out of the left column in the final sum
can be discarded, in this case. But in general you
must be careful with it. See the following pages.

Check the answer by converting to decimal representation and doing the addition in that base (the same numbers are being added, but now represented in a different way, so the sum is the same.) 

  
   01111 110
    0110 1110  =  11010
  + 0001 0111  =   2310
    ---------    -----
    1000 0101  =  13310

QUESTION 4:

Do the following: 

  
    10  
  + 01  
   ----