While working on the final Sixth Grade Interactive Notebook Unit on Equation and Inequalities I started thinking about the algebraic reasoning skills that I would, in an ideal world, LOVE for my students to know coming to me. Modeling equality is the first thing that came to me as in my experience students have a difficulty showing that two sides of an equal sign must balance when you start throwing in variables.
Modeling equations starts as early as first and second grade when students are learning fact families and showing that despite numbers being in different places in the equation they are still equal.
To help students understand the Addition or Subtraction Property of Equality, work in a small group of students (or even as an entire class under the document camera) and display one of the cards.
Using a scale level students should model each side of the equation with similar objects. This can also be done on white boards or with an actual balance and unifix cubes.
One way that many students will show that sides are equal is building a group of ten on each side (if possible) and then counting the extra objects to determine that each have the same.
Another method that students might take is to add the same amount to each side to make them equal. You can see that with this one the blocks were added to make the pictures similar.
Subtracting on a balance is a little bit different. Students should model the subtrahend on both sides of the balance.
Then by subtracting the minuend from each side students can easily see the amount left they can see that both sides of the equation are equal.
These cards (and 22 others) are in the Modeling Equality FREEBIE in my Teachers Pay Teachers Store. Click on the picture below and grab it today to use in your classroom.