Mathematics

Beginner

50 mins

Teacher/Student led

Learning Goals

Learning Outcomes

Lesson Files

+80 XP

Teacher-led from the board — pupils need no device

What you need:
IWB/Projector/Large Screen

Decimals on the Number Line to Thousandths

Pupils place decimals to thousandths on a number line by zooming in on the relevant section, recognise equivalent decimals, and find decimals between two given values.

Warning: Your screen size is quite small for viewing this. Rotate your device into landscape mode if you can.

1 Getting Started
2 Watch and Notice
3 Try It Together
4 Sketch the Line in Your Copy
5 Class Challenge
6 What Did We Notice?
7 What's Next
Pupil practice

Your turn

Your teacher is running this lesson on the board. Here is the part you can try yourself.

Your written work is on page 8

Number line

1 - Getting Started ~4 mins

Here is a stretch of number line that runs from 0.4 up to 0.5. Where do you think 0.45 would sit on it? And here is a harder one: where would 0.456 go?

Tip

Have a good look before anyone answers.

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~8 mins

Here are three number lines, each showing a tighter stretch than the last. Notice how the marks get finer on each one, and see where each decimal lands.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~11 mins

Key point

First, a quick check on trailing zeros. Watch the board: I place 0.5, then 0.50, then 0.500 — all three land on exactly the same point, because a trailing zero adds no value. Five tenths, fifty hundredths, five hundred thousandths: same spot, written three ways.

Now we work on the 0.3 to 0.4 line, with each small mark worth one thousandth. We will place three decimals in this order: 0.305, then 0.342, then 0.388. Watch how each one climbs a little higher along the same line.

Placing thousandths on the 0.3 to 0.4 line

+15 XP

4 - Sketch the Line in Your Copy ~3 mins

COPYBOOK MOMENT

Illustration for Sketch the Line in Your Copy In your maths copy, use a ruler to sketch a number line from 0.3 to 0.4 with a mark every 0.01. That gives you ten evenly spaced steps along the line: 0.30, 0.31, 0.32, all the way up to 0.40.

These marks only reach hundredths, so our three thousandths decimals sit between two marks. For each one, first draw a small arrow to the nearest hundredth mark, then draw a tiny dot to show roughly where it lands between the marks.

0.305 sits between 0.30 and 0.31, halfway between them (five thousandths along).
0.342 sits between 0.34 and 0.35, close to 0.34.
0.388 sits between 0.38 and 0.39, close to 0.39.

+10 XP

5 - Class Challenge ~8 mins

Key point

Today we work through these placements together on the same 0.3 to 0.4 line: place 0.305, then place 0.342, then place 0.388 — and finally the trickiest one, find a decimal that sits between 0.34 and 0.345.

Place decimals on the 0.3 to 0.4 line

+15 XP

Pupil practice

Module 1 · Place Value, Decimals and the Number System Number

Lesson 8 · Decimals on the Number Line to Thousandths

Download Activity Book page (PDF)

123learn · Online learning platform

Unlock the full learning experience

You're previewing this lesson. Get full access to this lesson and hundreds more — each one ready to teach, with interactive activities, printable resources and pupil progress tracking built in.

Hundreds of curriculum-aligned lessons

Interactive activities in every lesson

Printable resources & progress tracking

Get started

Copyright Notice
This lesson is copyright of 123Learn.ie 2017 - 2025. Unauthorised use, copying or distribution is not allowed.