## Base 10 Blocks on Jamboard for Subtraction

### The Jamboard

The Jamboard has images of basic base 10 blocks. The background provides side by side tables for numbers and for blocks. Additional blocks are set aside for regrouping. Here is a FB Reel and a YouTube video showing how to use this artifact.

Here is a link. You need to make a copy to access it

## This post presents a Google Jamboard manipulative activity to help scaffold the act of subtraction which helps unpack the concept of subtraction.

### Overview

The Jamboard can be individualized with Google Images. The can allow for context. In this example, maybe the context is there are 7 players and 4 have an injury or on COVID protocol and have to sit out.

The artifact also incorporates scaffolding, color coding, and manipulatives. Subtraction is an operation, which invokes a verb. The kinesthetic aspect of the manipulatives helps to unpack the concept of subtraction.

### Steps

1. Write the problem, using color.
2. Circle the starting amount in the row as the same color as the initial number.
3. Populate the row with the images of interest to the student.
4. Physically take away the identified amount.
5. Write the remaining amount as the answer.

Here is the link to the Jamboard. You need to make a copy to access it.

## 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.