Addition Strategies: Doubles and Double Plus 1

posted Jan 11, 2013, 6:47 AM by Patrick Johnson   [ updated Jan 11, 2013, 7:25 AM ]
This week students have been exploring mental addition strategies. The strategy we have been working on is using doubles to help find the sum of other number facts.

Students, with a partner, practiced their addition facts by adding 2 number cubes together (one of the number cubes has numbers on it and the other number cube has dots). 

Afterwards we sat in a circle and practiced our double facts. I showed each students a plate with numbered dots. The student had to say what the number was and what was the number was doubled (we talked about a few strategies on doubling numbers).

Next students and their partners each got 2 numbered cubes, graph paper and coloured pencils. Student had to graph each of their rolls and write the addition fact underneath. Afterwards, we placed their results on our bansho wall and discussed the math. We learned that double facts produced rectangle shapes. We also learned that double facts will always produce rectangles even when working with greater sums. We also discussed the sums where the shape was a rectangle plus one additional square (a double plus one like 5+6) and how knowing our double facts can help us solve double plus one and other math facts.