Can be done as a worksheet, but I personally cut up the sheets, place them in differentiated boxes at the front of the class, and get the children to write their answers in their books. Once a child has done one problem, they can go back to their box and collect a new one.
Love the pirate theme. But in a word problem I think it should be fewer,not less, when talking about amounts. It is less when you say 40 less than 30. If someone could confirm or deny this I would appreciate it.