Add vs Subtract Concepts – Kinesthetic Approach

In working with students who have fallen significantly behind in math, a common challenge is adding and subtracting. This can manifest in word problems or simple add and subtract problems. When this is the case, the first thing I check is whether the student understands conceptually what addition and subtraction are. Here is a Google Slides file that shows the approach I use. (You can make a copy and then edit.) I copy and paste slides for subsequent days so the Google Slides file services as a repository of the trials – data collection.

Each slide as the same format.

  • The operation in bold font.
  • The primary pile with the objects to work with.
  • The secondary pile with objects used for addition prompts.
  • The garbage can for objects discarded in subtraction prompts.

I like to use pennies as objects but will use Google Images of topics the student likes if I need something extra to keep their interest and attention. The student is tasked with performing an action with the objects and to distinguish between tasks to show discernment of what action to perform, relative to the prompt. There are 3 operations types: addition, subtraction, and sorting. The sorting is used simply as a distractor. Each image shows the original slide and a slide of the final product. The slides can be copied to for additional prompts. This first round focuses on common language that speaks to addition and subtraction.

In the next round, the sorting is removed and the language is focused on the terms add and subtract as a step in shaping understanding of the eventual symbols.

Finally, the actual symbols are used. If the student gets confused the previous language can be used as a prompt.

Addition: Concept and Mechanics

The graphic organizer below is used to show the student the steps for addition. It also addresses the concept of addition (which I have addressed previously) as an act of pulling “together” two parts to form a whole.

The student is prompted to move the first part (set of coins in this case) to the number chart. This can be completed with 1 to 1 correspondence or with subitizing (identifying the number of items without counting). Then, the student is prompted to move the second part while counting on, e.g. 7, 8 etc. (as opposed to starting from the left and counting from the first coin: 1, 2 etc.). The chart scaffolds the counting on and allows the student to see the total as a magnitude.

It is important to first teach the students the “rules of the game”, i.e. how to use the graphic organizer. To do this have the student simply move the first part to the number chart then the second part. The student can also be prompted to state the addition problem (written at the top). When the student is fluent with these steps the counting on can be implemented.

The next step would be to replace the coins with the symbolic representation, numbers.

So Easy?!

Problems like the addition problem below are often viewed by adults as straight forward. This perception can make it difficult for adults, including teachers and even special education teachers to help students who struggle with it.

I find that the math teacher candidates and special education teacher candidates struggle with breaking down math topics, especially “easy” ones like the one below, into simple steps. To help students who struggle with math breaking down the math topic is imperative. The analogy I use is to break the topic down into bite-sized pieces like we cut up a hot dog for a baby in a high chair.

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For new teachers I use a formal task analysis approach to teach candidates how to cut up the math into bite-sized pieces. A task analysis for the problem above was an assignment given to a group of graduate level special ed candidates. As is common, they overlooked many simple little steps hidden in the problem. These steps are hidden because they are so simple or so automatic in our brains that we don’t think about them. See below for how I break this topic into several pieces or steps. For example, before even starting the addition the person doing the problem has to identify that 43 is a 2-digit number with 4 in the TENS place and 3 in the ONES place. Understanding that the problem is addition which entails pulling the numbers together to get a total (sum) is an essential and overlooked step. If a student struggles with a step the step can be addressed in isolation, as I show in another blog post.

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Adding ones digits in 2 digit numbers with carrying

A major obstacle in math for many students with special needs is carrying in addition problems. Below is a task analysis approach.

First, I target the step of identifying the ONES and TENS place in the 2 digit sum in the ONES column (below it is 12). In a scaffolded handout I create a box to for the sum with the ONES and TENS separated. At first I give the sum and simply have the student carry the one.

sum of ones given.jpg

Then I have the student find the sum and write it in the box (14 below). Once mastered I have the student write the sum and carry the 1.

sum of ones given

They would have mastered adding single digit numbers before this lesson. I revert back to single digit numbers to allow them to get comfortable with writing the sum off to the side without the scaffolding. (In the example below I modeled this by writing 13.)

sum of ones with color no scaffolding

The last step is to add the TENS digits with the carried 1. I use Base 10 manipulatives to work through all the steps (larger space on the right is for the manipulatives) and have the student write out each step as it is completed with the manipulatives.

sum of ones with carrying with base 10 blocks first

Finally, the student attempts to add without the scaffolding. I continue with color but then fade it.

adding 2 digit numbers with carrying with color no scaffold