I love the time of year when we can start working on addition and subtraction strategies in math. There are three key strategies that I like to teach my students that draw on other important math understandings that we have been working on throughout the year. You can purchase the activities shown below here!
Understanding the Concept of addition/subtraction
Before even starting to teach addition and subtraction strategies, I want to make sure that my students understand the actual concept first. I don’t want them to just memorize equations, but rather to really know why we add or subtract. I like to use numberless story problems to start developing this understanding. It helps to showcase the why behind the adding and subtracting while taking out the pressure of the numbers. It also helps show off the process of solving story problems. You can check out more information on numberless story problems here or purchase a set of my digital numberless story problems here.
I also like to use the books If I Were a Plus Sign or If I Were a Minus Sign to help introduce the concept of writing equations and the different symbols involved. (Accompanying class book activity linked here and books are linked with Amazon affiliate link for your convenience)
Since most of the first half of the year is spent developing students’ counting skills, it’s only natural that the first addition and subtraction strategy we teach continues this counting development with tools that the children are already familiar with. We can use number lines, ten frames, dice, and counters to teach the strategies of counting on or counting backwards. All of these tools should be available to students when working on addition and subtraction (and counting) and students should be given the chance to try out different tools and strategies to see which one is best for them.
Students will probably start by counting all – counting all the counters or counting all the dots on the dice. This is perfectly natural. Once they feel secure with counting all, then you can encourage them to try counting on or backwards as a more efficient strategy.
Once students have some experience with counting to add or subtract, you can teach them to use drawings for solving math problems. They will be counting with the drawings, but the drawing is a more abstract way to solve the problem, as it doesn’t involve actual objects. This also means that it is a strategy that students can use anywhere and anytime. An important lesson to have with students is the difference between math drawings and other drawings. The purpose of math drawings are to solve a problem – so we want to be quick about drawing them. The purpose is not to make the most beautiful drawings ever. I like to tell my students that they should use circles, squares, or triangles as the symbols in their drawings.
Knowing fact families
The goal of teaching addition and subtraction is to truly understand the purpose behind it. However, we do want students to be fluent with putting numbers together and breaking numbers apart so that students can quickly manipulate numbers to solve harder problems. This means that we want students to know some basic fact families. In my school district, we want students to know all the facts to five fluently by the end of kindergarten and facts to ten by the end of first grade.
I use a variety of different games to practice breaking apart numbers and increase fact fluency. Kathy Richardson has a variety of games that are perfectly aimed at this skill. I also like to use bingo and the fact puzzles to practice fact fluency.
When teaching addition and subtraction, we want to be purposeful about teaching strategies that build off of the students’ counting development. We want students to really understand why we add and subtract and to learn different strategies for solving problems so students can find a strategy that works best for them and will support them in their eventual fact fluency.