Number Bonds to 20

Building upon our work on learning the number bonds to 10 (posted about here and here) and their understanding of partitioning, we then expanded this knowledge to calculate and so memorise the number bonds to 20 - with the overall aim of improving their mental maths skills.

I began by giving them a quick oral quiz on which numbers "matched" with each other to give a total of 10, i.e. "What do you add to 2 to make 10?" We then revised what they knew about partitioning numbers into tens and units by going through a couple of examples together on the whiteboard - stopping on the number 20.

I then explained to them how they could use the number bonds to 10 to calculate what number they needed to make a total of 20, because 20 is simply 10 more than 10! I gave them a couple of examples on the whiteboard (e.g. see picture above) then quizzed them to check their understanding.

Finally, I gave them some pages photocopied from Letts Make It Easy... Maths & English (Age 5-6) and Letts Monster Maths - Maths (Age 5-6) to recap and reinforce.

The bottom of the first page (left) was a good opportunity to teach them the importance of showing their working out, in terms of keeping track of what they're doing and working things out step by step, in order to pick up on where they might have made a mistake.