# Complementary events

In this lesson, we will look at how we can calculate probabilities for complementary events.

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.When you roll a fair six-sided dice, it is harder to roll a six than a four.

1/5

Q2.In a group of ten people, the probability that at least two were born on the same day of the week is 1.

2/5

Q3.There is an even chance of it raining on any given day.

3/5

Q4.If I roll a fair six-sided dice, I am more likely to get an even number than an odd number.

4/5

Q5.Since a football team can either win, lose, or draw, the probability that they win must be one third.

5/5

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.When you roll a fair six-sided dice, it is harder to roll a six than a four.

1/5

Q2.In a group of ten people, the probability that at least two were born on the same day of the week is 1.

2/5

Q3.There is an even chance of it raining on any given day.

3/5

Q4.If I roll a fair six-sided dice, I am more likely to get an even number than an odd number.

4/5

Q5.Since a football team can either win, lose, or draw, the probability that they win must be one third.

5/5

# Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

# Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Complementary Events

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.There are 20 guests at a party. 12 of them are drinking coffee and the rest are drinking tea. What is the probability of selecting one who is drinking tea?

1/5

Q2.There are 18 marbles in a bag. 13 of them are not green. What is the probability of selecting a green marble?

2/5

Q3.The probability that it rains tomorrow is 0.4. What is the probability it is sunny?

3/5

Q4.There are 100 cars in a car park. 40 of them are yellow. What is the probability of choosing a car that is not yellow?

4/5

Q5.The probability that it will snow tomorrow is 0.05. What is the probability that it won't snow?

5/5

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Complementary Events

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.There are 20 guests at a party. 12 of them are drinking coffee and the rest are drinking tea. What is the probability of selecting one who is drinking tea?

1/5

Q2.There are 18 marbles in a bag. 13 of them are not green. What is the probability of selecting a green marble?

2/5

Q3.The probability that it rains tomorrow is 0.4. What is the probability it is sunny?

3/5

Q4.There are 100 cars in a car park. 40 of them are yellow. What is the probability of choosing a car that is not yellow?

4/5

Q5.The probability that it will snow tomorrow is 0.05. What is the probability that it won't snow?

5/5

# Lesson summary: Complementary events

## Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Jog

On the spot:
Dance