Start with a history of piracy. Discuss with your child how the increased trade of nations by ships created an increase in robbery at sea. Explore the reasons why trade by ship became so popular and discuss how this began to change countries which had previously been isolated. Compare what goods a pirate would find when he attacked and robbed a ship in the Mediterranean Sea or a ship off the coast of Africa versus a pirate who robbed ships of the Caribbean Sea.
History will naturally take you to geography as you examine the way the world looked from 1519 to 1780, the Golden Age of Piracy. You can find maps of the trade routes and the pirate haunts of those days. Compare these maps to the way the world looks today. Encourage your child to examine the geographical reasons why certain shipping routes were subject to piracy.
Study the biographies of the more popular pirates--or your child's personal favorite pirate. Look into that pirate's background and country of origin. Considering his home country, the time period he lived in and the shipping route he haunted, discuss what his daily habits may have been. Examine what he may have worn or eaten and whether he partook of rum and tobacco. Compare pirate facts to popular fiction to see how close or distant the two may be.
Pillage and plunder for a math exercise. You and your child can be pirates, each with her own treasure. You could also have someone be a ship full of goods and someone else be the pirate. Measure the goods and treasure in units and add, subtract, multiply or divide as the treasure is stolen or as more treasure is accumulated. You can also tackle fractions with questions such as, "If one quarter of the treasure is stolen, how much is left?"