Plotting Three Digits

Overview

In this lesson, students identify and place three-digit numbers on a number line. They practise counting forward and using benchmarks (such as 100 and 200) to locate numbers accurately.

Learning intentions

• Students will identify three-digit numbers and match them to positions on a number line.
• Students will use place value (hundreds, tens, ones) to support their plotting.
• Students will check their answers by counting and comparing distances between numbers.
• Students will explain how they found a number line position using simple mathematical language.

Success criteria

• I can locate and plot a given three-digit number on a number line.
• I can use landmarks (100, 200, 300…) and count accurately to reach my number.
• I can explain whether my number is too small or too big and correct it.
• I can match my plotted position to the correct written number.

Curriculum links

• Number and place value: representing, partitioning and working with whole numbers up to at least three digits.
• Number lines and counting: using number lines as tools for counting, comparing and ordering whole numbers.
• Mathematical reasoning: describing strategies and checking solutions for reasonableness.
• Communicating: using everyday and mathematical language to explain how numbers relate on a line.

Lesson structure (30 minutes)

1. 3 min — WALT and warm-up count

• Say WALT: “We are learning to identify three-digit numbers on number lines.”
• Use a large classroom number line (or projected) from 0 to 300. Call out a few three-digit numbers (e.g., 120, 205, 278). Students show the position with a finger and then say the number aloud.

2. 5 min — Teacher model: landmarks and counting in tens

• Draw a number line 0–300 with marks every 10 (0, 10, 20… 300).
• Model placing 234:
• Find the benchmark 200.
• Count forward by tens to 230.
• Then use the ones/middle mark logic to place 234 (show how each small step represents 1 when the line includes smaller intervals, or explain if using “tick subsets” such as highlighting 230 then moving 4 ticks).
• Emphasise “hundreds → tens → ones” and “count on to check”.

3. 6 min — Guided practice: partner plotting

• Provide each pair with a worksheet card showing a number line and 4 numbers to place (mixture of easy and moderate).
• Pairs take turns reading a number, pointing to the expected location, and placing the token/circle.
• Teacher circulates, using prompts: “What hundred is it near?” “How many tens forward from 200?” “What do you notice about your position?”

4. 7 min — Individual check: ‘Find and justify’

• Students complete 5 quick plots independently on a lined response sheet.
• Include a simple written check sentence: “I found it by counting from ___.”
• For students needing extra support, provide partially marked number lines (fewer ticks) and a “hint” strip showing landmarks (e.g., 100, 200, 300).

5. 6 min — Game: Too small / Just right / Too big

• Teacher calls a number (e.g., 146). Students hold up a card (or mini whiteboard mark) showing one of three choices: too small, just right, too big relative to a displayed student example.
• Repeat with 1–2 additional examples, quickly revisiting correct reasoning and how to adjust.

6. 3 min — Exit ticket: one perfect placement

• Each student plots one three-digit number on a mini number line (0–300). Choose one number that matches their current ability range (teachers pre-select).
• Students hand in; teacher quickly checks placement and counting approach.

Resources

• Large number line (0–300) on board, or projected
• Student number line worksheets with ticks (some pre-marked landmarks)
• Coloured counters or paper circles/tokens for plotting
• Mini whiteboards and markers (optional)
• “Hint strip” with landmarks (100, 200, 300) and place value icons (H, T, O)
• Too small / Just right / Too big cards
• Exit ticket slips with a small number line
• Pair work materials (one set of tokens per pair)

Assessment

• Observation during partner plotting: listen for place value language and counting strategies.
• Marking the independent plots: accuracy of position and correctness of the strategy sentence.
• Exit ticket: confirms readiness for the next lesson (e.g., more complex intervals on the line).

Differentiation

• Support:
• Provide marked number lines (ticks every 10 only) first, then gradually introduce smaller intervals.
• Use landmarks and place value cues (hundreds/tens/ones colour-coding).
• Offer sentence starters: “I started at ___ and counted on by ___.”
• Pair neurodivergent learners with a supportive partner and allow finger-pointing/counting on the line.
• Extension:
• Give a second number line that has mixed intervals (e.g., some gaps of 5) and ask students to place two three-digit numbers and explain the adjustment.
• Challenge students to create and share a personal number line with at least one benchmark and two missing numbers they design.
• EALD:
• Pre-teach key phrases using visuals: “landmark”, “count on”, “move forward”, “near 200”.
• Keep instructions short; model one worked example; provide bilingual-friendly number word support if available.
• Allow oral responses alongside written responses.
• SEN/Neurodivergent:
• Reduce load by focusing on fewer plots with higher quality checking.
• Use movement breaks during the game and allow verbal counting rather than only written work.
• Provide a “checking routine” card: landmark → count tens → finish ones → check by counting back or re-reading.

Extension (optional)

• Students create a personal number line (0–300) using the class template: include 3 landmarks, mark enough ticks for counting, and write 3 three-digit numbers of their choice to place. They swap with a partner who plots and then checks by counting on from the nearest landmark.