Add and Compare

Overview

In this lesson, students practice addition within 20 by solving short word problems using objects, drawings, and equations with a symbol for the unknown. The lesson also builds fluency with strategies (like counting on and making ten) and connects addition to subtraction facts.

Learning intentions

• Students will solve addition word problems within 20 using objects, drawings, and equations.
• Students will represent an unknown number in a math sentence with a blank or symbol (? ).
• Students will use counting on or making ten to add within 20.
• Students will explain how their strategy helps them find the answer.

Success criteria

• I can solve an “adding to” or “putting together” word problem within 20.
• I can write an equation for the problem with? for the unknown.
• I can use a strategy like counting on or making ten to solve.
• I can show my thinking with a drawing, objects, and/or number sentence.

Curriculum links

• Operations and Algebraic Thinking — solve word problems within 20 using addition and subtraction, with unknowns in all positions, using objects, drawings, and equations with a symbol for the unknown number.
• Operations and Algebraic Thinking — add and subtract within 20; demonstrate fluency for addition and subtraction within 10 using strategies like counting on and making ten.
• Operations and Algebraic Thinking — determine the unknown whole number in an addition or subtraction equation with three whole numbers.

Lesson structure (25 minutes)

1. 0–3 min · Warm-up (quick facts). Teacher shows two teen number cards (example: 8 and 5) and asks students to name one sum strategy they could use; students turn and talk, then share one idea (counting on or making ten).
2. 3–8 min · Mini-lesson: making tens in addition. Teacher models with base-ten blocks or ten-frames: show 8 + 6 by making ten (8 + 2 = 10, then 10 + 4 = 14) and records the steps as a number bond or drawing; students copy the drawing and verbalize the steps together.
3. 8–15 min · Guided practice: “adding to” with unknown. Teacher reads: “Jada has 7 stickers. She gets some more. Now she has 13 stickers. How many did she get?” Teacher places 7 counters on a mat, then covers the rest with a “?” space and asks, “What do we need to find?” Students use counters/drawings to determine the missing addend and write an equation: 7 +? = 13 (teacher circulates and prompts “How did you make your ten?”).
4. 15–20 min · Guided practice: “putting together” with unknown. Teacher says: “At the park there are some kids on the slide and some kids on the swings. There are 12 kids total. There are 5 on the slide. How many are on the swings?” Teacher draws two parts and a total, then students solve and write an equation: 5 +? = 12 (or? + 5 = 12); teacher checks for correct use of? and correct answer).
5. 20–23 min · Fluency link: connect addition to subtraction. Teacher asks a quick question using one problem’s numbers: “If 7 + 6 = 13 is true, what subtraction fact matches it?” Students respond with a related equation (example: 13 − 7 = 6) and explain briefly how it connects.
6. 23–25 min · Exit ticket (quick check). Teacher gives one prompt: “There are 10 books. Some more are added. Now there are 14 books. How many were added? Write an equation with?.” Students answer independently.

Resources

• Small counters or linking cubes (enough for 5 students)
• Base-ten blocks or ten-frames (or paper ten-frames)
• Drawing paper and pencils
• Word problem cards (two guided problems + one exit ticket)
• Equation sentence strips with a blank and a “?” option
• Timer or visual agenda for 25 minutes

Assessment

• During guided practice, teacher listens for correct strategy use (counting on or making ten) and correct equation with a symbol for the unknown.
• Quick checks in step 4 for accurate representations (two parts and a total) and correct use of? in the equation.
• Exit ticket collects: correct unknown number and an equation like a +? = total (or? + a = total).

Differentiation

• Support: Provide sentence starters on paper: “I know __ because __.” and “My equation is __ +? = __.”
• Support: Offer a partially completed ten-frame or drawing template to reduce drawing load.
• Extension: For students who finish early, ask them to write the matching subtraction equation (example: if 7 + 6 = 13, then 13 − 7 = 6).
• EAL/SEN: Read problems twice, point to the numbers on the board, and allow students to respond using counters or drawings before writing the equation.