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Year 8 · Key Stage 3 · free KS3 maths weekly check

Weekly check: Year 8 part 2

20 mixed questions from 9 Year 8 topics, 50 marks. It covers compound measures to angles in polygons, the second third of the year in the order schools usually teach it.

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The questions

1

A straight line passes through the points (1, 7) and (3, 13).

Find the equation of the line.

Give your answer in the form y = mx + c

3 marks
Show answer
y = 3x + 4
See the working

Gradient

change in y=13 - 7
=6
change in x=3 - 1
=2
m=change in ychange in x
m=62
m=3
Substitute (1, 7) into y = 3x + c
7=3 × 1 + c
7=3 + c
-3c=4-3
Check with (3, 13)
3 × 3 + 4=13

y = 3x + 4

2

Show each inequality on its number line.

  1. x ≥ −2
  2. −1 < x ≤ 4
−5−4−3−2−1012345a−5−4−3−2−1012345b
2 marks
Show answer
a) solid circle at -2, arrow to the right b) open circle at -1, solid circle at 4, line joining them
See the working

Solid circle = included (≤ or ≥), open circle = not included (< or >)

a)

Solid circle at -2

Arrow to the right

Solid circle at -2, arrow right

b)

Open circle at -1

Solid circle at 4

Join them

Open circle at -1 to solid circle at 4

3

A model of a car is made to a scale of 1 : 24.

  1. The model is 18 cm long. Work out the length of the real car in metres.
  2. The real car is 1.44 m high. Work out the height of the model in centimetres.
3 marks
Show answer
a) 4.32 m b) 6 cm
See the working

Real = 24 × model

a)

18 × 24 = 432 cm

432 ÷ 100 = 4.32

4.32 m

b)

1.44 m = 144 cm

144 ÷ 24 = 6

6 cm

4

The diagram shows two parallel lines crossed by a straight line.

One of the marked angles is 71°. The angle marked x° is the co-interior angle between the parallel lines on the same side of the crossing line.

Work out the value of x. Give a reason for your answer.

71°x°Diagram NOT accurately drawn
3 marks
Show answer
x = 109 (co-interior angles between parallel lines add up to 180 degrees)
See the working

Co-interior angles add to 180°

x + 71=180
-71x=109-71

x = 109

Co-interior angles add up to 180°

5

A pattern of shapes tessellates if the shapes fit together around every point with no gaps and no overlaps.

  1. Explain why regular hexagons tessellate.
  2. Explain why regular pentagons do not tessellate.
  3. Ella makes a floor tile pattern where two regular octagons and one square meet at every point. Show that this pattern has no gaps.
3 marks
Show answer
a) Each interior angle is 120°, and 3 × 120° = 360°, so three hexagons fit exactly round a point. b) Each interior angle is 108°; 3 × 108° = 324° leaves a gap and 4 × 108° = 432° overlaps, as 360 is not a multiple of 108. c) 135° + 135° + 90° = 360°.
See the working

a) hexagon

360 ÷ 6=60
180 - 60=120
3 × 120=360

3 hexagons make 360° exactly

b) pentagon

360 ÷ 5=72
180 - 72=108
3 × 108=324
4 × 108=432

324° leaves a gap, 432° overlaps

c) octagon angle = 135°, square = 90°

135 + 135 + 90=360

360° so no gaps

6

Here are the first four terms of an arithmetic sequence.

7   12   17   22

Explain why 81 is not a term of this sequence.

2 marks
Show answer
Every term of the sequence ends in 2 or 7, and 81 ends in 1
See the working

7, 12, 17, 22, 27, 32, ...

Terms go up in 5s

Every term ends in 2 or 7

81 ends in 1

Or use the nth term 5n + 2

5n + 2=81
-25n=79-2
÷5n=15.8÷5

15.8 is not a whole number

Every term ends in 2 or 7, and 81 ends in 1

7

A is the point with coordinates (2, 4).

B is the point with coordinates (8, 10).

Work out the coordinates of the midpoint of AB.

2 marks
Show answer
(5, 7)
See the working

Midpoint: mean of each coordinate

x=2 + 82
x=102
x=5
y=4 + 102
y=142
y=7

(5, 7)

8

The diagram shows the speedometer of a car.

  1. Write down the speed shown on the speedometer.
  2. Use 5 miles = 8 kilometres to change this speed to km/h.
020406080100120mph
3 marks
Show answer
a) 70 mph b) 112 km/h
See the working

a) Each small mark = 10 mph

Halfway between 60 and 80

70 mph

b)

70 ÷ 5 = 14

14 × 8 = 112

112 km/h

9

The diagram shows an inequality on a number line.

Write down the inequality shown, using x.

−3−2−10123456
2 marks
Show answer
-1 <= x < 4
See the working

Solid circle at -1: included

x≥-1
Open circle at 4: not included
x<4

Put them together

-1 ≤ x < 4

10

The diagrams show a triangle and a quadrilateral.

  1. Work out the size of angle x.
  2. Work out the size of angle y.
52°73°xDiagram NOT accurately drawna84°108°77°yDiagram NOT accurately drawnb
2 marks
Show answer
a) 55° b) 91°
See the working

a) angles in a triangle add to 180°

52 + 73=125
x=180 - 125

x = 55°

b) angles in a quadrilateral add to 360°

84 + 108 + 77=269
y=360 - 269

y = 91°

11

DE and FG are parallel straight lines.

Triangle ABC is drawn so that A lies on DE, and B and C both lie on FG.

D is to the left of A and E is to the right of A.

Angle DAB = 48° and angle ACB = 63°.

Work out the size of angle BAC.

Give a reason for each stage of your working.

48°63°ABCDEFGDiagram NOT accurately drawn
4 marks
Show answer
69°
See the working
ABC=DAB
ABC=48°
Alternate angles are equal
BAC=180° - 48° - 63°
BAC=69°

Angles in a triangle add to 180°

69°

12

A, B and C are three vertices of a parallelogram ABCD.

A is (−4, −1), B is (1, −1) and C is (3, 3).

  1. On the grid, plot the points A, B and C.
  2. Work out the coordinates of D.
−5−4−3−2−112345−5−4−3−2−112345Oxy
3 marks
Show answer
a) A (-4, -1), B (1, -1) and C (3, 3) plotted b) (-2, 3)
See the working

a)

A (-4, -1), B (1, -1), C (3, 3)

A, B and C plotted

b)

DC is parallel to AB and the same length

A to B: 5 right, 0 up

so D to C: 5 right, 0 up

D = (3 - 5, 3 - 0)

D (-2, 3)

13

Simplify

  1. 5a2 + 3a − 2a2 + 4a − 9
  2. 4xy − 7 + 2yx + 10
2 marks
Show answer
a) 3a2 + 7a - 9 b) 6xy + 3
See the working

a)

a2 terms: 5a2 - 2a2 = 3a2

a terms: 3a + 4a = 7a

3a2 + 7a - 9

b)

yx is the same as xy

4xy + 2xy = 6xy

-7 + 10 = 3

6xy + 3

14

Two angles fit together on a straight line. One of the angles is 64° and the other angle is y°.

  1. Work out the value of y.
  2. Give a reason for your answer.
2 marks
Show answer
a) 116 b) angles on a straight line add up to 180 degrees
See the working

a)

y + 64=180
-64y=116-64

y = 116

b)

Angles on a straight line add up to 180°

15

Here are four pieces of algebra.

A:  3x + 2 = 11     B:  A = lw     C:  4y − 7     D:  2(x + 3) ≡ 2x + 6

Write down which one is

  1. an expression
  2. an equation
  3. a formula
  4. an identity
2 marks
Show answer
a) C b) A c) B d) D
See the working

a)

expression: no equals sign

C

b)

equation: true for one value (x = 3)

A

c)

formula: works out one quantity from others

B

d)

identity: true for every x, the ≡ sign

D

16

Here are the first four terms of an arithmetic sequence.

5   9   13   17

Find an expression, in terms of n, for the nth term of the sequence.

2 marks
Show answer
4n + 1
See the working

5, 9, 13, 17

Common difference = +4

4n: 4, 8, 12, 16

Each term is 1 more than 4n

nth term=4n + 1
Check n = 3
4 × 3 + 1=13

4n + 1

17

Solve w4 + 2 = 9

2 marks
Show answer
w = 28
See the working
w4 + 2=9
-2w4=7-2
×4w=28×4

w = 28

18

Dan and Ella share 45 sweets.

Ella gets 7 more sweets than Dan.

Dan says, "I got 20 sweets."

Is Dan right? You must show how you get your answer.

3 marks
Show answer
No, Dan got 19 sweets
See the working

Dan = d, Ella = d + 7

d + d + 7=45
2d + 7=45
-72d=38-7
÷2d=19÷2
Check
19 + 26=45

No, Dan got 19 sweets, not 20

19

A straight line has equation y = 3x − 2

  1. Write down the gradient of the line.
  2. Write down the coordinates of the point where the line crosses the y-axis.
2 marks
Show answer
a) 3 b) (0, -2)
See the working

Compare with y = mx + c

y = 3x - 2

a)

m=3

3

b)

c=-2

Crosses the y-axis where x = 0

(0, -2)

20
  1. The first term of a sequence is 7. The term-to-term rule is "multiply by 2 then subtract 3". Write down the first four terms.
  2. The first term of another sequence is 50. The term-to-term rule is "subtract 8". Write down the first five terms.
3 marks
Show answer
a) 7, 11, 19, 35 b) 50, 42, 34, 26, 18
See the working

a)

7 × 2 - 3 = 11

11 × 2 - 3 = 19

19 × 2 - 3 = 35

7, 11, 19, 35

b) - 8 each time

50, 42, 34, 26, 18

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Every question here is original and written by Robinson Tuition, drawn from the Year 8 topic worksheets. It follows the Key Stage 3 programme of study.

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