At this point, you may wish to read another of the books listed in the Bibliography of Counting Books, for example, What Comes in 2’s, 3’s and 4’s. While students remain in their seats, ask them to name things that come in pairs. Record their responses and ask the children to say or write the addition equations the list of pairs suggests. Then ask a volunteer to choose a pair and state the addends and the sum.
You may also wish to discuss some examples from science, such as “If a starfish has 5 arms, how many arms will 2 starfish have?”
Or, ask students “If a flower has 4 petals, how many petals will 2 flowers have?”
Now ask the children to write an addition story problem that uses doubles. Encourage them to share their problem with a friend and add it to their portfolios.
When the students complete this activity, give groups of students a set of Double 6 dominoes, and ask them to put the tiles upside down. Tell the students to take turns picking a domino and finding the sum in any way they wish. If they
pick a double (a domino with the same number of spots on both sides) they should write the equation it suggests. If the tile picked is not a double, it is simply removed from the pile and the next child draws. Play continues until all tiles are drawn. The winner is the child who drew the most doubles. As this game takes only a little time, the students may wish to play it more than once.
Next, provide the children with index cards from which 2 inches of the long side have been cut. Ask them to fold the 3-inch squares to make two right triangles and then to cut the triangles apart. Ask them “How many triangles will we need if we want enough for each doubles fact found on our dominoes?” If the answer “6” is given, remind them that there is a 0+0 domino also, and that they will each need seven cards. Then have children write one doubles fact on each triangle by writing the sum at the right angle and the addends across the hypotenuse, one in each corner. When the students are ready, call them together to display the cards that they created. Encourage them to practice their addition facts with doubles by having a friend cover the sum and show the addends only. You may wish to have the children draw a sample triangle fact card and write its associated addition facts as an entry in their portfolio.
