One of my favourite festive resources is this 'Santa's Reindeer' resource from Michael Sharman
You can download this resource from the TES by clicking on the above link.
Here's a print screen of the resource...
I also give my students a grid of all 16 numbers and the number facts they need to use to help them formalise their workings. They use the grid as a tick sheet to tick off whether the numbers adhere to the number facts or not.
This resource is one of many featured in the TES Mathematics 'Maths at Christmas' collection.
You can view the full collection at: