Answer :

Question is: how many 84s will fit in 5376? Let's think about some easy multiples:

84 * 100 = 8400, so it's too big
84 * 10 = 840, so it might work

84 | 5376 | 10
       -840

84 | 4536 | 10
       -840

84 | 3696 | 10
       -840

84 | 2856 | 10
       -840

84 | 2016 | 10
       -840

84 | 1176 | 10
       -840

84 | 336

We can't fit any more 840 in 336, so we check how many 84s are in 336 and what's the remainder:

84 | 336 | 4
     - 336

So there's no remainder. Now we add all the partial quotients to get the final result:

10 + 10 + 10 + 10 + 10 + 10 + 4 = 64

It's correct, I checked it with calculator. I just hope you'll be able to read something from that, it's quite difficult to do partial dividing with no pencil and paper :)