Do you find that your students have difficulty explaining the way to solve an addition problem?
According to John Van De Walle, “Research has demonstrated that children will invent a lot of different strategies for addition and subtraction. Your goal (as an educator) might be that each of your children has at least one or two methods that are reasonably efficient, mathematically correct, and useful with lots of different numbers.”
In addition, the Standards of Mathematical Practice state that we should provide students opportunities to make choices and try out potential solution paths to answer problems. When teaching, let’s first question students to see how they would solve a problem.
If we notice that they can only describe a procedure using the traditional algorithm (“carry the one”), we can step in and encourage them to try some additional addition strategies that build base ten understanding. These strategies develop deeper conceptual understanding and reinforce the use of mental math. One such strategy is modeled below:
Using the partial sums strategy allows the students the opportunity to add the numbers based on their place. Add the tens with the tens and the ones with the ones. In this way, the students can see that adding 7 + 9 yields 16. Thus our students notice that the 1 in 16 is represents ten. This strategy works to reinforce and support place value.
I want to encourage you to try using various addition strategies with your students that support base ten understanding and connect numbers.