Duration: 45 minutes
By the end of this lesson, you will be able to:
What we've learned so far:
Two people walk for 1 hour:
Who is faster?
John is faster!
Why?
Key insight: Speed depends on both distance AND time!
How can we find speed?
If we know:
There must be a way to calculate speed!
Let's discover the formula together.
Let's look at three scenarios:
Scenario A: Car travels 60 km in 1 hour Scenario B: Car travels 120 km in 2 hours Scenario C: Bicycle travels 30 km in 2 hours
How can we find the speed in each case?
Car travels 60 km in 1 hour
That was easy! When time is 1 hour, speed equals the distance.
Car travels 120 km in 2 hours
Think: In 1 hour, how far does it go?
We divided distance by time!
Bicycle travels 30 km in 2 hours
Calculate:
Again, we divided distance by time!
To find speed, we DIVIDE distance by time
SPEED = DISTANCE ÷ TIME
Using letters:
S = D ÷ T or S = D/T
Where: S = Speed, D = Distance, T = Time
S = D ÷ T
What it means:
The formula makes sense!
Think about it:
As time increases, speed decreases (if distance stays same)
A matatu travels 80 km in 2 hours. Find its speed.
UNDERSTAND: Find speed; given distance and time PLAN: Use S = D ÷ T WORK:
A person walks 12 km in 3 hours. What is their speed?
UNDERSTAND: Find speed; D = 12 km, T = 3 hours PLAN: S = D ÷ T WORK:
A cyclist covers 200 metres in 10 seconds. Find the speed.
UNDERSTAND: Find speed; D = 200 m, T = 10 sec PLAN: S = D ÷ T WORK:
Calculate the speed:
Distance = 100 km Time = 2 hours
Use the formula: S = D ÷ T
Write your answer in your exercise book.
UNDERSTAND: Find S; D = 100 km, T = 2 hours PLAN: S = D ÷ T WORK:
Did you remember the units?
Distance = 45 km Time = 3 hours
Show all four steps!
UNDERSTAND: Find S; D = 45 km, T = 3 hours PLAN: S = D ÷ T WORK:
Important insights:
A helpful memory tool:
D ___ | | | S | T |___|
To find S: Cover S, you see D ÷ T We'll learn D and T formulas in the next lesson!
Why this formula matters:
Don't do these:
Forget to divide (just writing the numbers) Add or multiply instead of divide Forget the units in your answer Mix up which is distance and which is time
Always use S = D ÷ T and include units!
A boda-boda travels 60 km in 2 hours. Calculate its speed.
Use the four-step method:
UNDERSTAND: Find speed; D = 60 km, T = 2 hours PLAN: Use S = D ÷ T WORK:
Key points to remember:
NCDC guidance:
"Encourage learners to derive the formula themselves because it will not only stick in their brain, but they will be able to use it appropriately when faced with such problems."
Understanding beats memorization!
This is early algebra!
Assignment:
Write the speed formula in three ways: in words, using letters, and explain what it means
Calculate speed (show all working): a) D = 60 km, T = 2 hours b) D = 120 km, T = 4 hours c) D = 15 km, T = 3 hours
A bus travels from Kampala to Jinja (80 km) in 2 hours. Calculate its speed.
Two matatus travel for 3 hours. Matatu A covers 120 km, Matatu B covers 90 km. Which is faster? Prove it.
Expected time: 25 minutes
Tomorrow we will learn:
This is exciting!
Created: January 11, 2026 Based on: NCDC P6 Mathematics Curriculum - Topic 8: Distance, Time and Speed
Source: National Curriculum Development Centre (NCDC), Uganda