Abstract
The purpose of this paper is to establish the learning phases for the choice of operation regarding word problems involving multiplication of decimal fractions. A research test and standards were developed to identify the learning phases. Three hundred and forty-four primary-school students ranging from fourth to sixth grade were tested. As results, four learning phases were identified the choice of operation in word problems involving multiplication of decimal fractions. In phase, I students can solve the word problems only with multiplication of integers, but can't solve the word problems with multiplication of decimal fractions. In phase II, students can not choose the operation in the word problems with multiplication of decimal fractions but calculate that operation. In phase III, students can choose and calculate the operation in the word problems with multiplication of decimal fractions. In phasd IV, students can choose and calculate the operation in the word problems through multiplication of decimal fractions based on the meaning of multiplication of decimal fractions.
