Use Equality

Overview

In this 30-minute lesson, students build on their understanding of addition and subtraction by learning that the equal sign means “has the same value as,” not “the answer comes next.” Using balance models, objects, and equations, students identify true and false equations and find a missing number.

Learning intentions

• Students will be able to explain that an equal sign shows two sides have the same value.
• Students will be able to decide whether addition and subtraction equations are true or false.
• Students will be able to find a missing whole number that makes an equation true.
• Students will be able to explain their thinking using objects, drawings, words, or equations.

Success criteria

• I can explain what the equal sign means.
• I can identify a true equation and a false equation.
• I can find a missing number that makes both sides equal.
• I can prove my answer with objects, a drawing, or an oral explanation.

Curriculum links

• Understanding the meaning of the equal sign and determining whether addition and subtraction equations are true or false.
• Determining an unknown whole number in an addition or subtraction equation relating three whole numbers.
• Solving addition and subtraction situations within 20 using objects, drawings, and equations.
• Mathematical practice: making sense of problems, using representations, and explaining reasoning.

Lesson structure (30 minutes)

1. 0–4 min · Hook: What does equal mean? Teacher opens the opening balance-scale question and displays a balance scale with 5 counters on one side and 5 on the other, then asks, “What do you notice? What does the equal sign tell us?” Students turn and talk, then share an explanation using the sentence frame, “Equal means both sides have ___.”

2. 4–9 min · Direct teach: Both sides have the same value. Teacher uses a balance scale or projected visual to model 4 + 2 = 6, then deliberately shows 6 = 4 + 2 and explains that the equal sign can appear in different places. Teacher contrasts this with 4 + 2 = 7 and emphasizes the bold equal sign and the phrase “same value as.” Students build each equation with counters and show thumbs up for true or thumbs down for false.

3. 9–16 min · Guided investigation: True or false? Teacher gives each pair counters and a small balance scale, if available, and displays the examples on the true-or-false investigation slides: 3 + 2 = 5, 7 = 4 + 3, 6 = 5 + 2, and 8 - 3 = 5. Teacher asks, “How can you prove it?” Students model both sides, compare the amounts, and explain whether each equation is true or false. The teacher listens for students who treat the equal sign as an answer signal and revoices: “You are checking whether both sides have the same value.”

4. 16–23 min · Independent practice: Complete the missing number. Teacher distributes the equality and missing-number worksheet and models one example: 5 + ___ = 8. Students use counters, drawings, or mental strategies to complete equations such as 6 + ___ = 10, ___ = 3 + 4, 9 - ___ = 5, and 7 = ___ + 2. Students circle whether selected equations are true or false and explain one answer to a partner. The teacher works with individuals or a small group using concrete objects and equations with one missing part.

5. 23–27 min · Reasoning share: Prove it. Teacher opens the reasoning and discussion slides and displays two equations, including 4 + 3 = 3 + 4 and 5 + 2 = 5 + 3. Students choose one, decide whether it is true or false, and share a proof using the frame, “I know it is ___ because both sides have ___.” Teacher highlights that numbers can be arranged differently and still have the same value when the totals match.

6. 27–30 min · Exit check and recap. Teacher shows the exit question slide and asks students to solve 8 = 5 + ___ and decide whether 6 + 1 = 6 + 2 is true or false. Students respond on paper, with counters, or orally to the teacher. Teacher closes by asking, “What does the equal sign mean?” and collects responses for next-lesson planning.

Resources

• the Use Equality slide deck
• the equality and missing-number worksheet
• Balance scales, one per pair if available
• Connecting cubes or counters
• Large equal sign and operation symbol cards
• Whiteboard and bold markers
• Pencils, crayons, and clipboards
• Optional number line to 20
• Small response cards labeled true and false

Assessment

• During modeling and investigation, check whether students compare both sides rather than simply calculate the expression before the equal sign.
• Review worksheet responses and listen for accurate use of “same value,” “true,” and “false.”
• Use the exit check to identify whether each student can complete a missing number and judge an equation; record whether support was concrete, visual, or verbal.

Differentiation

• For students needing support, use a balance scale, counters, large symbol cards, and equations within 10. Build each side physically before recording the equation.
• Provide uncluttered equations with generous spacing, bold operation and equal signs, one problem at a time, and a visual model beside the equation. Read directions aloud and allow students to answer orally, point, draw, or use counters.
• For dyslexia-friendly access, use a clear sans-serif font, high contrast, minimal decoration, consistent left-to-right layout, and no unnecessary text. Avoid copying large lists and provide the sentence frames orally and in print.
• For students ready for a challenge, ask them to create two different true equations using the same three numbers, then create a false equation and explain how to change one number to make it true. Students may explore arrangements such as 4 + 3 = 3 + 4.

Extension

• Invite advanced learners to create a “true equation puzzle” for a partner using a missing number in any position.
• Ask students to find three different equations with the same value and justify why each one is true.