Jump Back on the Number Line

Overview

Students learn to subtract a one-digit number from a number to 20 by counting backwards on a number line. The lesson uses movement, teacher modelling, partner talk and pictorial recording so students connect the action of “taking away” with a written subtraction equation.

Learning intentions

• WALT subtract a one-digit number from a number to 20.
• WALT use a number line to count backwards accurately.
• WALT explain how the number line shows a subtraction problem.
• WALT record subtraction equations using numerals and symbols.

Success criteria

• I can start at the first number in a subtraction problem.
• I can jump backwards the correct number of ones.
• I can say and write the number I land on.
• I can explain my answer using a number line.

Curriculum links

• Mathematics and Statistics — Number: counting forwards and backwards, and understanding subtraction as taking away.
• Mathematics and Statistics — Number: representing and solving additive problems within 20.
• Mathematics and Statistics — communicating mathematical thinking using drawings, materials, language and symbols.
• Mathsteasers: building confidence and deepening understanding through higher-order mathematical thinking.

Lesson structure (45 minutes)

1. 0–5 min · Warm-up: Count and move. Teacher displays a large floor number line from 0 to 20 using the number-line warm-up slides and calls numbers for students to stand on, then asks them to take one, two or three steps backwards. Students count aloud as they move and describe what happens to the number when they move back.

2. 5–12 min · Connect to subtraction. Teacher shows 8 counters, removes 3, and asks, “How many are left?” Record (8 - 3 = 5), then connect each removed counter with one backward jump from 8 to 5 on the subtraction connection slides. Students act out “8 take away 3”, identify the starting number, the number of jumps and the answer, and rehearse the sentence: “I started at __, jumped back __, and landed on __.”

3. 12–20 min · Explicit teaching and modelling. Teacher models examples such as (14 - 2), (17 - 5) and (12 - 8), always circling the starting number, drawing equal-sized backward jumps and counting each jump once. Use the teacher modelling slides to reveal one step at a time; emphasise that the first number tells us where to start and the second number tells us how many ones to jump back. Students use finger movements to track each jump and answer carefully selected questions such as, “Why did we start at 17?” and “How do we know we made five jumps?”

4. 20–31 min · Partner number-line activity. Teacher pairs the 16 students and gives each pair a mini number line and counters; display the instructions on the partner activity slides. One student chooses or receives a subtraction equation within 20, places a counter on the first number, and moves it backwards one space for each one-digit amount; the partner checks the jumps and says the complete equation. Students swap roles after each turn and record at least four equations on the number-line subtraction worksheet.

5. 31–39 min · Independent application. Teacher distributes the number-line subtraction worksheet and supports students to solve problems such as (9 - 4), (15 - 3), (18 - 7) and (20 - 6), encouraging them to draw or trace their jumps rather than guess. Students complete the problems, circle their answers and choose one example to explain to a partner using the sentence frame.

6. 39–45 min · Wrap-up and assessment. Teacher revisits the wrap-up and exit-question slides, displays (16 - 4), and invites a student to demonstrate it on the class number line while another student explains the jumps. Students complete a quick oral exit check: solve (13 - 5), show the jumps with fingers or a drawn number line, and explain where they started and where they landed.

Resources

• the complete number-line subtraction slide deck
• the number-line subtraction worksheet
• Large floor number line labelled 0–20
• Mini number lines labelled 0–20, one per pair
• Small counters or linking cubes
• Whiteboard and pens
• Pencils and crayons
• Prepared subtraction equations within 20
• Exit-check problem displayed on the board

Assessment

• During the warm-up and modelling, listen for accurate backward counting and check whether students identify the correct starting number.
• During partner work, observe whether students make one jump per one and match the number of jumps to the subtrahend. Ask, “Show me how you know.”
• Use the final (13 - 5) explanation to identify students who can independently represent and communicate subtraction; record students needing further practice with numbers to 10 before extending to 20.

Differentiation

• Support learners with a number line beginning at 0, counters, finger tracking and equations with smaller numbers, such as (7 - 2). Count the jumps together and use the sentence frame, “I started at __ and jumped back __.”
• For students who need additional processing time, provide a highlighted starting number and let them physically move a counter before recording the equation.
• Offer visual and oral instructions, repeated modelling and partner rehearsal for English language learners and students with communication or learning needs.
• Extend confident students by asking them to create two different subtraction equations with the same answer, or to identify and correct an intentionally drawn number-line error.