This video reviews page 20 of the CGP book, 11+ Maths for the GL test, and shows how I would explain this page to a child.
To make best use of this video, you'll need a copy of the book.
Watch this video.
Ask the pupil to attempt the page. If the child gets through it all with no mistakes, then simply move on to the next page.
However, if anything needs explaining, this video should give you the confidence to do so.
As always, I hope you find this useful.
When purchasing this book, make sure you are getting the exact same title:
11+ GL Maths Practice Book & Assessment Tests - Ages 9-10 (with Online Edition) (CGP GL 11+ Ages 9-10)