P4-P6 Mathematics: what we throw away — building a broken line graph from official figures

• StageP4-P6
• SubjectMathematics
• Learning strandreflection on the application of AI
• Official documentsAI Literacy Learning Framework for Primary and Secondary Schools (Examples of Application Scenarios)
• Session timeOne lesson (60 min), in four segments

Pupils fetch the same official figure for four or five years themselves, round off the data, build a broken line graph, describe the trend in two or three sentences and peer-assess a classmate's work: two pages, fixed.

• AudienceTeachers Students
• ThemeHong Kong inquiry

• EquipmentProjector; printed worksheet (two pages, fixed); squared paper or the grid on the worksheet; the official data source the teacher names (pupils look it up themselves); ruler and colour pencils
• Version1.1
• Last updated2026-10-18

A line on a graph can be clear, and it can mislead. This worksheet has pupils draw their own, then peer-assess it: does this line say what the data actually says?

What this solves

At Key Stage 2, mathematics asks pupils to build a broken line graph and read the trend off it. It looks like an easy thing to hand to a tool: type the numbers in, the graph comes out. The cost is that pupils no longer make the judgements that are actually hard — whether the axis intervals are equal, where each point belongs, whether to round off the data, where the unit goes, and what the line is allowed to let you say.

This worksheet hands those judgements back to pupils, and it is fixed at two pages: page one fetches the data, rounds it off and draws the graph; page two carries the verification table (no more than five rows), the description of the trend and the peer assessment. The page count is fixed so that it is a complete classroom worksheet rather than a summary squeezed onto one page.

This resource supplies no waste figures at all. Pupils fetch the data themselves from the official source the teacher names, and record the source and the year in the verification table. Any number that appears on this page is fictional, printed only to show the format; it is not a data source, and it may not be used as an answer.

Where the topic comes from: using waste as the context for practising broken line graphs is this resource’s own choice of topic. The official example uses a different context. This page does not present waste as the official example’s topic, and a teacher may substitute another topic for their own school without changing the worksheet’s structure.

Learning objectives

Pupils will be able to:

1. Fetch the same figure for four or five years from the official source the teacher names, and record the source and the year.
2. Round off the data in the unit specified, and state how it was rounded.
3. Build a broken line graph on squared paper: a title, both axes named with units, equal intervals, and each point labelled with its value.
4. Describe the trend in two or three sentences, writing only what the graph shows and making no predictions.
5. Peer-assess a classmate’s work against the criteria, naming one thing done well and one thing to change.

How to use it

One 60-minute lesson, in four segments, on a two-page worksheet.

Segment 1 — fetch the data (15 minutes)

The teacher names one official source (a government statistics release or a departmental annual report, for example) and specifies that pupils take the same figure, in the same unit, for four or five consecutive years. Pupils look the figures up themselves and write the year, the figure as published, and the source name and year into the verification table on page one.

The table holds no more than five rows: one header row and four rows of data. The last year is left for pupils to fill in themselves, so that the whole class does not copy one figure without looking it up.

Segment 2 — round off the data (10 minutes)

The teacher specifies the place to round to (the nearest hundred or thousand, for example). Pupils round each figure, write it in the last column and note how it was rounded.

Worked example (fictional — not a data source): 12,345 tonnes rounded to the nearest thousand is 12,000 tonnes. This line shows the format only and may not be copied into the verification table.

Once rounded, the graph uses the rounded values only, and every point on one line is rounded to the same place.

Segment 3 — draw the graph (20 minutes)

On squared paper, pupils do five things:

1. Write a title that says which figure this is, for which place or scope, over which period.
2. Put years on the horizontal axis and the figure on the vertical axis, with units on both.
3. Keep the vertical intervals equal, and label the values on the axis.
4. Plot one point per year, and label each point with its value.
5. Join neighbouring points with straight lines (a broken line graph) — not a smooth curve.

Segment 4 — describe and peer-assess (15 minutes)

Pupils first write two or three sentences of their own: between which years the line rises or falls, where it is steepest, and whether any year sits apart from its neighbours. Only what the graph shows; no reasons.

Pairs then peer-assess against the criteria on page two, tick each item, and say aloud one thing done well and one thing to change. The teacher closes by showing two pieces side by side on the projector, focusing on the intervals and the units.

The timing assumes 60-minute lessons and the lesson is designed to finish in one, in no more than four segments.

Answer key and marking notes

A graph that meets the standard shows all five

Common errors

• Unequal intervals. If each square on the vertical axis stands for a different amount, the slope of the line no longer shows the change.
• Half the job. The table uses rounded values and the graph uses the published ones, so the two disagree.
• Treating the years as continuous. A missing year joined up anyway tells the reader there was data for it.
• A description that predicts. “Because there is more takeaway food” is a cause, not something the graph shows; only the latter is marked here.
• No title or unit. A line with no unit can be read as anything at all.

Peer-assessment criteria (pupils tick each)

Marking is process-based: a verification table with sources and years, a stated method of rounding, and a graph that matches the table — all three and the work meets the standard. This page requires no modelling, weighting or assumptions; those belong to a later stage and are outside what is marked here. If pupils raise them, note them but do not score them.

Files

What we throw away: broken line graph worksheet (editable Word document)

Includes: two pupil pages — page one with the five-row verification table, the rounding example and the grid; page two with the trend description, the peer-assessment criteria and a self-check — plus a one-page teacher edition (how to run it, marking notes, common errors). Schools may reuse and adapt it.

Official documents

Every resource in this library is written to the AI Literacy Learning Framework for Primary and Secondary Schools and falls within the policy scope of the Blueprint for Digital Education Development in Primary and Secondary Schools.

This resource maps to:

• AI Literacy Learning Framework for Primary and Secondary Schools (Examples of Application Scenarios) (p.6): the Key Stage 2 mathematics example on building broken line graphs, in which pupils build a graph from official data, round off the data and use peer assessments to review one another’s work. This worksheet keeps all three practices and changes the context to the waste topic it sets for itself.

Learning strand: reflection on the application of AI

Official documents page: https://www.edb.gov.hk/en/edu-system/primary-secondary/applicable-to-primary-secondary/it-in-edu/debp.html

This page is an independent Beets teaching resource, not an official EDB document.

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