We know that Bonnie has 47 stickers at the end. We also know that after she has given away 1/6 of her stickers she was got 12 more. So, we can subtract the 12 from the the 47 to get 35. This is how stickers Bonnie has after she has given away 1/6. In order to find the original amount, we need to set up an equation:
35 = x - x/6 (x is the starting amount, before giving away 1/6)
We set this up in this manner so that we can reach 35. The x by itself is the original amount of stickers and the x/6 is one sixth of the original amount. So, if we subtract 1/6 of the original amount we should be left with 35. All that is left to do is solve for x. You should find that 5x = 210.
I hope this helps and makes sense!