Year 4 · Fractions and decimals
Comparing and rounding decimals
Compare numbers with the same number of decimal places up to two decimal places, and round decimals with one decimal place to the nearest whole number
Lesson overview
What you'll learn in this lesson
Compare numbers with the same number of decimal places up to two decimal places, and round decimals with one decimal place to the nearest whole number
Key learning points
- • Compare tenths first
- • Same number of decimal places
- • Rounding to the nearest whole
- • Rounding in real life
This lesson at a glance
- 20 minutes
- 19 parts to scroll through
- 4 quick checks
- No marked quiz yet
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 19
Watch first
Comparing and rounding decimals
See how a fraction and a decimal can be exactly the same amount.
Do it for real
The practicals below use what the film shows, with a full method you can follow at home.
In a nutshell
Compare numbers with the same number of decimal places up to two decimal places, and round decimals with one decimal place to the nearest whole number
What you already know
Part 2 of 19
Before we start
What you already know
You can write tenths and hundredths as decimals.
Key words
Part 3 of 19
Key words
Words you'll need today
- tenths
- The first digit after the decimal point.
- hundredths
- The second digit after the decimal point.
- round
- Move to the nearest whole number.
Learning cycle
Part 4 of 19
Learning cycle 1 of 2
Part 1 — Comparing
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 5 of 19
Learn
Compare tenths first
Is 0.9 or 0.15 bigger? Tenths: 9 beats 1, so 0.9 is bigger. Writing 0.9 as 0.90 makes it obvious — 90 hundredths against 15 hundredths. Adding a zero on the end never changes a decimal's value.
Explore the idea
Part 6 of 19
Learn
Same number of decimal places
Compare 3.42 and 3.24. Wholes match, tenths: 4 beats 2, so 3.42 is greater. Just like whole numbers, you work left to right and stop at the first column that differs.
Quick check
Part 7 of 19
Quick check
Which is larger: 0.7 or 0.68?
Quick check
Part 8 of 19
Quick check
2.35 ? 2.53
Reset break
Part 9 of 19
Pause
That's sitting 1 of 2 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 10 of 19
Learning cycle 2 of 2
Part 2 — Rounding
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 11 of 19
Learn
Rounding to the nearest whole
Look only at the tenths digit. 4.3 rounds to 4 because 3 tenths is less than half. 4.7 rounds to 5. 4.5 is exactly halfway, and the rule is to round up, so it becomes 5.
Explore the idea
Part 12 of 19
Learn
Rounding in real life
A 2.6 km walk is 'about 3 km'. £7.40 is 'about £7'. Rounding is for talking and estimating, not for the till — the exact number is still the one you pay.
Quick check
Part 13 of 19
Quick check
Round 6.4 to the nearest whole number.
Quick check
Part 14 of 19
Quick check
Round 9.5 to the nearest whole number.
Common mix-ups
Part 15 of 19
Common mix-ups
Things people often get wrong
- Thinking 0.15 > 0.9 because 15 > 9.
- Rounding 4.49 up to 5 by looking at the 9 instead of the tenths digit.
- Believing 0.5 and 0.05 are the same.
Challenge round
Part 16 of 19
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 17 of 19
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Adding a zero on the end never changes a ____'s value.
Just like whole ____, you work left to right and stop at the first column that differs.
Rounding is for talking and estimating, not for the till — the exact ____ is still the one you pay.
Mastery quiz
Part 18 of 19
No quiz for this one
This lesson has no marked quiz attached yet.
Lesson round-up
Part 19 of 19
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
Not played
Points this lesson
0
Best run
0 in a row
Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?
Ask LunaDo the work
Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
The cost of a school trip
A school is planning a trip to a wildlife park. The coach costs £480 however many people go. Entry costs £9.50 for each pupil and each adult goes free. The school says every pupil must pay the same amount, and the trip must not lose money.
If 60 pupils go, the coach works out at £8 each, so the total for each pupil is £17.50. If only 40 pupils go, the coach works out at £12 each, so the price rises to £21.50. The teacher explains that the coach is a fixed cost and the entry is a cost per person — which is why the price per pupil changes when the number changes.
The school decides to charge £20 and to use anything left over for a second trip later in the year.
Written for Good Learning Co.
Reading questions
- Work out the total cost of the trip if 50 pupils go.
- Show why the price per pupil falls when more pupils go, using numbers.
- At £20 each, how many pupils must go before the trip makes money? Show your working.
Working out
Working outDo the practice questions on paper, showing every step — not just the answer. Mark them yourself and circle anything you got wrong.
10–15 questions
Worked example, explained
WritingCopy one question out and write underneath, in words, why each step works.
1 question, 4–5 sentences
Problem in words
Working outWrite your own real-life problem that uses today's method, then solve it.
1 problem + solution
Saved as you type.
Part 1 of 19 · Watch & discover