This is an easy change you can make to most board games to include a little more addition.
You need a snakes and ladders board game and dice.
When playing a board game like snakes and ladders there are lots of opportunities for your children to count.
One easy change you can make to include more addition is to make sure you use two dice instead of one.

You are playing Snakes and Ladders.
Use roll two dice and move the total. Nothing unusual so far.
...but what if you changed the rules a little:
Let your children decide what to do with the dice numbers.
For example, do they want to:
...add the dice and move forwards by that total?
...move backwards by the total of the two dice?
...move forwards by one dice and back again by the other?
Play the game a few times with each rule and see which everyone prefers.
If you want to play and don't have a Snakes and Ladders board you could work with your children to make your own.
Draw a 10 x 10 grid on a sheet of paper or card (an old cereal box turned inside out is perfect). Number the squares, be sure to get your children to help with this. Then (the fun bit) is when you all decide where to draw on the ladders and the snakes.
Slightly easier, is to download a pre-drawn board. We like this simple printable version on the edu-games website.

If you plan on playing the game a lot, then we can heartily recommend this vintage-looking version of Snakes and Ladders from 'Tobar'. Available in most toy shops and here linked to Amazon.
Amazon Affiliate link