Mathematics·Probability·conceptual
Complementary events
Understand and apply the rule that probabilities of all mutually exclusive outcomes sum to one; use this to find the probability of a complementary event (P(not A) = 1 − P(A))
Suggested ages 11–13
Evidence of understanding
- Verify that probabilities of all outcomes listed for a spinner sum to 1
- Calculate the probability of NOT rolling a 6 as 1 − 1/6 = 5/6
- Identify an error in a probability distribution where the values do not sum to 1
Assessment prompt
If a spinner has three sections and one has a probability of 0.4 and another has 0.35, can Complementary events work out the probability of landing on the third section without being told?
Standards alignment
7.SP.5US · ccss-math
Understand that the probability of a chance event is a number between 0 and 1
Common Core State Standards for Mathematics · 7
7.SP.7aUS · ccss-math
Develop a uniform probability model
Common Core State Standards for Mathematics · 7
KS3.Maths.Prob.2GB · uk-nc-2013
Sum of Probabilities
The national curriculum in England: Key stages 1 and 2 framework document · Key Stage 3