T4 · W1 · 2026
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Secondary 1 · Term 4 · Week 1

Maths & Science
Interactive Exercises

Mathematics — Unit 16
Science — Unit 9
25 questions · self-marked
📐 Mathematics 🔬 Science
📐
Mathematics · Unit 16

Interpreting & Discussing Results

Section A — Stem-and-Leaf Diagrams
The diagram below shows scores of 16 students in a science quiz (out of 50). Key: 2 | 1 = 21   8 | 3 = 38
Back-to-Back Stem-and-Leaf: Quiz Scores Left (lower) Stem Right (upper) 9 2 1 3 7 8 5 2 3 0 4 6 9 7 3 4 2 5 5 0 Total: 16 students
M1
How many students scored more than 35?
2 marks
students
M2
Find the median score of all 16 students.
2 marks
points
M3
Find the range of all scores.
1 mark
points
M4
Which stem has the most leaves on the right side? What does this tell you?
2 marks
A
Stem 2 — most students scored in the 20s
B
Stem 3 — most students scored in the 30s ✓
C
Stem 4 — most students scored in the 40s
D
Stem 5 — the highest scorer was in the 50s
Section B — Pie Charts
A survey asked 60 students about their favourite sport. Use the table to answer the questions.
n=60 students
SportStudentsAngle
⬤ Football24calculate →
⬤ Badminton1590°
⬤ Swimming12calculate →
⬤ Basketball9calculate →
M5
What is the angle for Football in the pie chart?
2 marks
Formula: Angle = (number of students ÷ total) × 360°
degrees
M6
What is the angle for Swimming?
1 mark
degrees
M7
Which sport was chosen by exactly a quarter of the students? How can you tell from the pie chart?
2 marks
A
Football — its slice is the largest
B
Badminton — its angle is 90°, which is exactly ¼ of 360°
C
Swimming — 12 out of 60 is one quarter
D
Basketball — its slice looks like a quarter
M8
What is the probability that a randomly chosen student picked Football? (Give as a simplified fraction — enter the numerator only, denominator is 5)
2 marks
/ 5
Section C — Using Statistics
Daily high temperatures (°C) in Jakarta over 9 days:
31   34   33   31   36   31   35   38   33
M9
Calculate the mean temperature. Round to 1 decimal place.
2 marks
°C
M10
Find the median temperature.
1 mark
°C
M11
What is the mode?
1 mark
°C
M12
Student says: "The mean is the best average to use here." Which statement best evaluates his claim?
2 marks
A
Student is correct — the mean always represents data best
B
Student is wrong — the mode (31°C) is pulled down by repeated low values, making the median (33°C) a better representative
C
Student is wrong — none of the averages can represent this data
D
Student is partly right — the mean and median are both reasonable here; the mode is low due to repeated 31s
M13 ⭐
Challenge: A 10th temperature is added, making the new mean exactly 33°C. What is the new temperature?
3 marks
°C
Maths score
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🔬
Science · Unit 9

Electromagnets

CELL + − SW IRON CORE N S coil of wire (solenoid) complete circuit when switch is closed
An electromagnet is a temporary magnet created when electric current flows through a coil of wire wound around a soft iron core. It can be switched on and off, and its strength can be varied.
S1
What happens to the magnetic field when the switch is opened (circuit broken)?
2 marks
A
The magnetic field gets stronger
B
The magnetic field reverses direction
C
The magnetic field disappears — the electromagnet stops working
D
The magnetic field stays the same
S2
Why is iron used for the core instead of steel?
2 marks
A
Iron is cheaper and easier to find
B
Iron is magnetically soft — it magnetises and demagnetises easily when current is switched on/off
C
Steel would melt under the heat of the current
D
Iron conducts electricity better than steel
S3
Give two advantages of an electromagnet over a permanent magnet. (Select both correct answers)
2 marks
A
It can be switched on and off
B
Its strength can be varied by changing the current
C
It never needs electricity to work
D
It is always stronger than a permanent magnet
Section B — Factors Affecting Electromagnet Strength
A student counts how many paperclips an electromagnet holds as she varies the number of coil turns (current kept constant).
TurnsPaperclips held
103
206
309
4011
5015
S4
What is the independent variable in this investigation?
1 mark
A
Number of paperclips held
B
Number of coil turns
C
The current through the wire
D
The type of iron core
S5
Which variable must be kept constant to make this a fair test?
1 mark
A
Number of paperclips
B
Number of coil turns
C
Current through the wire (voltage)
D
Colour of the wire insulation
S6
Which statement best describes the relationship between turns and strength?
2 marks
A
As turns increase, strength decreases
B
There is no clear pattern
C
As turns increase, strength increases — roughly proportionally
D
Strength only increases after 30 turns
S7
Predict how many paperclips would be held with 60 turns.
2 marks
paperclips
Section C — Real-World Applications
S8
A scrapyard electromagnet sorts steel cans from aluminium cans. Why does this work?
2 marks
A
Steel and aluminium have different colours, which the magnet detects
B
Steel is magnetic (iron-based) so it is attracted; aluminium is non-magnetic so it is not
C
The magnet heats the steel so it melts away from the aluminium
D
Both are attracted equally but steel is heavier so it falls off first
S9
Hospital MRI machines use very powerful electromagnets. Why must patients remove all metal objects beforehand?
2 marks
A
Metal objects get wet and cause the machine to malfunction
B
The powerful magnet attracts metal objects at high speed — creating a danger of injury and interference with the scan
C
Metal objects block the radio waves used in the scan
D
Metal heats up inside the MRI and could burn the patient
S10 ⭐
Extension: Name three changes that would make an electromagnet stronger using the same battery. Select all three correct answers.
3 marks
A
Increase the number of coil turns
B
Wind the coil more tightly (reduce gaps between loops)
C
Use a thicker or longer iron core
D
Use a steel core instead of iron
E
Replace the iron core with a plastic rod
Science score
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