First we calculate how much candy she has in total.
4 bags x 65 pieces = 4 x 65 = 260
Then add the extra 20 her father gave her, 260 + 20 = 280
Now we divide the total by 6 and the remainder is for herself.
280 / 6 = 46.666 pieces of candy between 6.
So we now move down to the next whole number, which is 46.
i.e. 46 x 6 = 276, so the remaining pieces of candy are 280-276 = 4 for Lan to keep for herself.
