"Complete equations involving addition whatever the position of an unknown, Complete a + b = …… for a and b < 9, Use subtractive writing to describe the situation of completion of a number to a given number, Go from additive equalities to subtractive equalities, Go from subtractive equalities to additive equalities, Choose the right operation (+ or -) to describe situations, Read a diagram associated with an operator and use it to determine the missing number, Determine the function +n or –n that links two sequences of numbers or magnitudes."