Loading please wait

The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Find the Probability of Selecting Specified Items

In this worksheet, students will calculate the probability of choosing or not choosing certain items.

'Find the Probability of Selecting Specified Items' worksheet

Key stage:  KS 3

Curriculum topic:   Probability

Curriculum subtopic:   Record, Describe and Analyse Probability Experiments

Difficulty level:  

Worksheet Overview

Probability can be written as a fraction.

On the top (numerator) of the fraction, we place the number of options we are looking for.

On the bottom (denominator) of the fraction, we place the total number of possible combinations.

 

 

Example

Look at these coloured cards.

 

coloured cards

 

What is the probability of selecting a red or blue card at random?

 

Answer

There are 2 options that "we are looking for". The red and the blue card.

There are 6 "possible combinations".

 

The probability of choosing a red or blue card is 2/6 which simplifies to 1/3.

 

Having done that, what is the probability of choosing a yellow card? 

There are 4 yellow cards out of a possible 6 cards, so the probability is 4/6 which simplifies to 2/3.

 

thumbs up

 

Can you see that the two answers of 1/3 and 2/3 add together to make the number 1? There is no other possible combination other than the ones we have looked at, so the total will be 1.

 

The probability of something happening, plus the probability of it not happening will always equal 1.

 

Let's have a go at some questions now.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started
laptop

Try an activity or get started for free