Show me the strategy to solve 339-284

Well what I used back when I learned Hundreds subtraction was to make a table that would have the big number on top and the small number on the bottom. Now to get started I would check if a number could go into another. So I in this problem I find that 84 cant be taken away from 39 so There is a method that I learned called the "carry over" or what my teacher called it borrowing. which is Taking the number with more value and adding it like a 10 to the second number down so in 339 the first 3 would turn into 2 so 239 and then I would pass it down so 2(13)9 so then I could do 13- 8 since of there values. so that leaves me with 259 since I took it away then I would do the next 9-4 is 5 so 255 and since I took away the 84 in 284 I would get left with 200 so the final equation is 255-200=? And the final answer is 55.  Hope this helped out please comment if you need any clarifying.

all it means is function 3