First, add Monday and Tuesday to get Wednesday, this would mean 53 (Monday) + 35 (Tuesday) = 88 (Wednesday). This brings the total to 88 (Monday Tuesday) + 88 (Wednesday), meaning the total so far is 176. Because they sold half of Wednesday on Thursday, it would be 88 (Wednesday) / 2, or 44 (Thursday). Adding 44 to our total of 176 creates 220. This means that throughout all the days, there were 220 pairs of shoes sold.