How Big Are Classes 5, 6 and 7?

Use the two sets of data to find out how many children there are in Classes 5, 6 and 7.

Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

Problem

Four pupils from Class 4, Ben, Ali, Katie and Charlene, decided to make graphs of the sizes of the seven classes in the school.

Ben and Ali found out how many children there were in Classes 1, 2 and 3.

Katie and Charlene found about Classes 5, 6 and 7.

Of course they all knew the number of children in Class 4.

Ben and Ali drew a bar chart. It looked like this:

Image
How Big Are Classes 5, 6 and 7?

 

Katie and Charlene drew this pictogram:

Image
How Big Are Classes 5, 6 and 7?

 

Kate and Charlene have forgotten to add a key to their pictogram. What should the key say?

How many children were there altogether in Classes 5, 6 and 7?