Fact Families Lesson
Begin by reading How Addition and Subtraction Became a Fact Family (get a copy at http://www.smashwords.com) while reading use a whiteboard/chalkboard with magnetic letters to show the number sentences used in the book.
After reading, ask students to give you examples of other fact families they can think of and use the board to show those.
Next, explain to students that they will make homes for the fact families in fact family city. Each student will get a piece of paper shaped like a house. In the roof the students will put the three numbers in the fact family and in the lower part of the house the four number sentences that go with that fact family (two addition, two subtraction). Use 3,5,8 from the book as the example on the board.
Then, send the students to their seats to independently work on their fact family house. When students finish bring them back together whole group to share the fact families they came up with and after sharing let them hang their house in a designated "City of Fact Family" area in the room. The teacher will need to have the area set up ahead of time and can really play it up with roads, other buildings, signs etc.
Last, have students share how they can use fact families to help them with word problems, addition problems and subtraction problems.