Subtraction Slip

Can you spot the mistake in this video? How would you work out the answer to this calculation?
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

This task focuses on the calculation

62 - 58

What do you notice about this calculation?

How would you work out the answer?

 

In the video below, you'll see someone calculating 62-58, but she makes a mistake.

Watch it all the way through. You may like to watch it more than once.



 

What is the mistake? How could she put it right?

Did you use the same method as the girl in the video? Why or why not?

 

Can you give an example of a subtraction calculation which you would solve using the method in the video, if you did not use it to solve 62-58?