“The barrier was that children were able to represent numbers using decipipes but.....”
Connecting representations on materials to their symbolic notation requires specific modelling and exploration. Here the link between number representations on decipipes and their location on a number line is clearly explained.
Domain: Place value
Transition: 6 → 7
Barrier: Linking decipipe representation of decimal numbers and their location on the number line.
Other resources:
Numeracy activities: