Chapter 6: Coordinates and straight-line graphs
A straight-line graph turns an algebraic rule into a picture whose gradient and intercept carry meaning.
Part of your national curriculum
- Algebra: Work with coordinates in all four quadrants and recognise, sketch and produce graphs of linear functions
Lesson overview
What you'll learn in this lesson
Work with coordinates in all four quadrants and recognise, sketch and produce graphs of linear functions
Key learning points
- • Coordinates
- • Generate a line
- • Read the structure
This lesson at a glance
- 32 minutes
- 14 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 14
Watch first
Chapter 6: Coordinates and straight-line graphs
An English teaching video on this topic from mathantics. Watch it, then scroll down for the lesson.
In a nutshell
Work with coordinates in all four quadrants and recognise, sketch and produce graphs of linear functions
Learning cycle
Part 2 of 14
Learning cycle 1 of 2
Part 1 · Coordinates
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 14
Learn
Coordinates
Coordinates are written (x,y): move horizontally first, then vertically. Negative coordinates locate points left of or below the origin.
Explore the idea
Part 4 of 14
Learn
Generate a line
For y = 2x + 1, choose x-values, calculate y, plot the points and join them with a straight line. Points include (0,1), (1,3) and (2,5).
Quick check
Part 5 of 14
Quick check
Which point lies in quadrant III?
Reset break
Part 6 of 14
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.
Quick check
Part 7 of 14
Quick check
For y=2x+1, find y when x=3.
Learning cycle
Part 8 of 14
Learning cycle 2 of 2
Part 2 · Read the structure
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 14
Learn
Read the structure
In y = mx + c, m is the gradient and c is the y-intercept. Parallel lines have equal gradients.
Quick check
Part 10 of 14
Quick check
What is the gradient of y=−3x+4?
Challenge round
Part 11 of 14
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 12 of 14
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ are written (x,y): move horizontally first, then vertically.
Mastery quiz
Part 13 of 14
Marked quiz
End of lesson quiz: Chapter 6: Coordinates and straight-line graphs
3 questions, marked with the reasoning shown. No timer.
1. Which point lies in quadrant III?
2. For y=2x+1, find y when x=3.
3. What is the gradient of y=−3x+4?
Lesson round-up
Part 14 of 14
Lesson round-up
Ready when you are
Quiz score
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Games
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Points this lesson
0
Best run
0 in a row
Luna: 0 out of 3 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 14 · Watch & discover
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Work with coordinates in all four quadrants and recognise, sketch and produce graphs of linear functions
