The concept of addition can be introduced in preschool or year 1 of schooling by joining groups together to see how many there are altogether, taking into consideration the 4 stage language model for mathematics when teaching the concept of addition.

2. THE CONCEPT OF ADDITION CAN BE EXPLAINED AS THE JOINING
OF GROUPS TOGETHER TO SEE HOW MANY THERE ARE ALL
TOGETHER.
INTRODUCING THE CONCEPT OF ADDITION WOULD START IN PREP
OR YR 1 OF SCHOOLING. WHEN TEACHING THE CONCEPT OF
ADDITION THE 4 STAGE LANGUAGE MODEL FOR MATHEMATICS
NEEDS TO BE TAKEN INTO CONSIDERATION.
(Jamieson-Proctor, 2012).