Part, Part, Whole
This is where the children learn that a number can be split in different ways.
Get a group of objects, I used grapes, and two bowls or containers.
Get your child to split the 4 objects between the two bowls and then count how many is in each. Get them to repeat this but putting a different number of objects in each of the bowls.
Look at the pictures below of how I did it.
As you go along, explain to them that 4 is 2+2 or 4 can be 3+1.
You can also do it the other way round 3+1 is 4 and 2+2 is also 4.