We explain doubling by saying that we are adding together two amounts which are exactly the same.
When we are teaching this in class, we generally use a ladybird or butterfly symmetry approach, where a paint spot is put on one side of the template and then folded over to create the double. The addition sentence is then written underneath the image. I emphasise how many spots can be seen on each side of the minibeast and make the link that these are the two numbers being added to create the double.
I am attaching templates for a butterfly and ladybird for you to try this at home.
I am also attaching some activity sheets for your child to work through. Once they have completed these, you could use doubles in a practical context. For example, if you give them 2 biscuits, you would need to double this amount to give a sibling the same amount. How many biscuits would that be? Maybe they could have a go at making up their own doubling word problems with fruit, toys, number of jumps etc. Or if you play a dice game, you could try double the dice score.