Sharing in a given ratio
A ratio tells you how many parts each share gets. Once you know the total number of parts, every ratio question becomes a division followed by a multiplication.
Part of your national curriculum
- Ratio, proportion and rates of change: Use ratio notation, including reduction to simplest form
- Ratio, proportion and rates of change: Divide a given quantity into two parts in a given part:part or part:whole ratio, and express the division of a quantity into two parts as a ratio
Lesson overview
What you'll learn in this lesson
Divide a quantity in a given ratio
Key learning points
- • Counting the parts
- • Keeping ratios in simplest form
This lesson at a glance
- 20 minutes
- 15 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 15
Visual introductionPicture this
Sharing in a given ratio
A ratio tells you how many parts each share gets. Once you know the total number of parts, every ratio question becomes a division followed by a multiplication.
In a nutshell
Divide a quantity in a given ratio
Explore the idea
Part 2 of 15
Learn
Counting the parts
In the ratio 3 : 2 there are 5 parts altogether. Divide the total by 5 to find the value of one part, then multiply back up for each share.
Explore the idea
Part 3 of 15
Learn
Keeping ratios in simplest form
Divide both sides by their highest common factor. 12 : 18 becomes 2 : 3. The relationship is unchanged — only the numbers get friendlier.
Reset break
Part 4 of 15
Pause
That's sitting 1 of 4 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.
Explore the idea
Part 5 of 15
Worked example
Worked example — a wildlife rescue centre
A rescue centre has 45 animals in the ratio 3 birds : 2 mammals. Parts = 5. One part = 45 ÷ 5 = 9. Birds = 3 × 9 = 27, mammals = 2 × 9 = 18. Check: 27 + 18 = 45.
Quick check
Part 6 of 15
Quick check
Part 7 of 15
Reset break
Part 8 of 15
Pause
That's sitting 2 of 4 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.
Quick check
Part 9 of 15
Quick check
A sanctuary keeps otters and seals in the ratio 5 : 3. There are 32 animals. How many otters?
Challenge round
Part 10 of 15
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 11 of 15
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ the total by 5 to find the value of one part, then multiply back up for each share.
Reset break
Part 12 of 15
Pause
That's sitting 3 of 4 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.
Challenge round
Part 13 of 15
Game · Recall cards
A recipe uses flour and butter in the ratio 3:2. You use 450 g of flour. How much butter?
Card 1 of 4
Mastery quiz
Part 14 of 15
Marked quiz
End of lesson quiz: Sharing in a given ratio
4 questions, marked with the reasoning shown. No timer.
1. A recipe uses flour and butter in the ratio 3:2. You use 450 g of flour. How much butter?
2. Share £84 in the ratio 5:2. What is the larger share?
3. Share 60 in the ratio 4 : 2.
4. Simplify 24 : 36.
Lesson round-up
Part 15 of 15
Lesson round-up
Ready when you are
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Ask LunaPart 1 of 15 · Watch & discover
How this is going
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Use ratio notation, including reduction to simplest form
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Divide a given quantity into two parts in a given part:part or part:whole ratio, and express the division of a quantity into two parts as a ratio