Representing a situation by an addition equation, Counting the union of two collections of objects, Using the writing a + b to describe a union situation of two sets, Illustrating a + b by a representation of objects, by image or with the help of a story, Reading and writing the equality a + b = c associated to a practical situation of union of two collections, Completing the equation, a + b = … by manipulating objects or by drawing, a less than 10 and b less than 10, Knowing that a sum of two terms is greater than each of its terms, Representing a situation with the help of the function “Add”.