This lesson comes near the end of my Understanding Equality where students have practiced comparing numbers, and then now comparing equations. The Common Core (1.OA.7) asks students to show that they have a conceptual understanding of the equals sign, and to prove whether or not equations are true or false. In this lesson, students show whether or not equations are equal by proving how much candy each candy bowl has.
Review past learning:
Yesterday we played a game where we had to figure out: Are we tied? And we talked about how tied means equal. Today we are going to prove whether or not an equation that has an equals sign is true or false.
Connect to the Real World:
The equals sign will help us throughout math-it helps us see that two statements represent the same amount.
Today, our goal is to think about: How can we prove that a number sentence is true or not?
I'll start the lesson by teaching students how to play the Candy Bowl game. We will practice the content by practicing the steps of the game.
Here are the rules for this game:
I’ll show an enlarged version of the Recording Sheet on chart paper. To model the game, I’ll pull 2 candy cards, one that says 4+4 and one that says 5-3. This pushes students to focus on the symbol (+ or -).
I’ll have 2 students come up to the chart paper, and each will work out one number sentence in the “candy bowl” circle.
Revisit Problem: Let’s go back to our number sentences. 4+4=5-3. Is that true or false? False. Why do we use the word false? False means not right and incorrect. That number sentence is not right - there is not the same on both sides.
I’ll have students practice this game on their own with two cards, this time with 18-2 and 15+1. The students have to show how they worked out each side of the problem. I’ll give them 5-7 minutes of work time at their desks. Students will record their thinking on the first set of candy bowls from the Recording Sheet.
I’ll have one student share how they solved each side.
So these number sentences are true because they have the same amount on both sides, even though the number sentences look different.
Students play the game with a partner.
To differentiate this activity for students, you can give students different materials. All cards and recording sheets are attached here: Recording Sheet.docx
Group A Cards:
Equations with numbers under 12. The recording sheet provides a scaffold for now, where students practice saying whether or not two equations are equal or not. These students will add the language of "true" and "false" once they have exhibited a conceptual understanding of "equal".
Group B Cards:
Equations with numbers under 20. Some equations have 3 addends.
Extension: Group C candy cards
These candy cards have more difficult equations on them. The equations set students up to try using different strategies to solve them. The strategies all come from 1.OA.6:
I'll present a new statement (8+1 = 3+6) and ask students to prove if it is true or false. The fun twist is that we will use real candy to prove it with a partner. Each partner will show their equation with Smarties and then we will see if the statement is equal. I'll have students show this on another row of their candy bowl recording sheet from the Game Time section.