Chapter 3: Substitution and formulae
A formula is a reusable machine: put values in carefully and it produces a result with meaning and units.
Part of your national curriculum
- Algebra: Substitute numerical values into formulae and expressions, including scientific formulae
Lesson overview
What you'll learn in this lesson
Substitute numerical values into formulae and expressions, including scientific formulae
Key learning points
- • Substitution
- • Scientific formula
- • Check the result
This lesson at a glance
- 28 minutes
- 16 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 16
Visual introductionPicture this
Chapter 3: Substitution and formulae
A formula is a reusable machine: put values in carefully and it produces a result with meaning and units.
In a nutshell
Substitute numerical values into formulae and expressions, including scientific formulae
Learning cycle
Part 2 of 16
Learning cycle 1 of 2
Part 1 · Substitution
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 16
Learn
Substitution
Replace each letter with its given value, using brackets around negative numbers. If a = −3, then a² means (−3)² = 9.
Reset break
Part 4 of 16
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 16
Learn
Scientific formula
Speed v = d/t. If distance d = 150 m and time t = 12 s, v = 150/12 = 12.5 m/s.
Quick check
Part 6 of 16
Quick check
Part 7 of 16
Reset break
Part 8 of 16
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.
Learning cycle
Part 9 of 16
Learning cycle 2 of 2
Part 2 · Check the result
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 16
Learn
Check the result
Estimate first, include units and ask whether the answer is sensible. Substitution errors often come from missing brackets or mismatched units.
Quick check
Part 11 of 16
Reset break
Part 12 of 16
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 16
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 14 of 16
Game · Recall cards
If x=4, find 3x+2.
Card 1 of 4
Mastery quiz
Part 15 of 16
Marked quiz
End of lesson quiz: Chapter 3: Substitution and formulae
4 questions, marked with the reasoning shown. No timer.
1. If x=4, find 3x+2.
2. Using v=d/t, find v when d=150 m and t=12 s.
3. If a=−3, what is a²?
4. Solve 4x − 5 = 19
Lesson round-up
Part 16 of 16
Lesson round-up
Ready when you are
Quiz score
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Points this lesson
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Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 16 · Watch & discover
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Substitute numerical values into formulae and expressions, including scientific formulae