This study investigated the role played by the referentials of whole and of half in the solving of addition of fractions by estimate. Middle class children (8 - 9 years old) at elementary school have solved the same addition of fractions but in different contexts: (i) by estimate, using the referential of half (Task 1), (ii) by estimate, using the referential of whole (Task 2), and (iii) by using the mathematical symbolism (Task 3). Although children were not able to solve the additions through the mathematical symbolism, they made appropriate estimates based on the referentials of whole and of half, showing the same good performance with both referentials. The conclusion was that reference points play an important role in mathematical reasoning.
adding fraction; mathematical knowledge; children; estimate; half and whole