The present study investigates the enactment of the mathematics curriculum in class 7 at a government school in Karachi. Using classroom observation, interviews of a teacher and sampled students and analysis of the curriculum document, the textbook and written work of the students, an attempt was made to understand how far the objectives of the elementary mathematics curriculum were being realised. Also, the constraints on the translation of these objectives from theory into practice were explored. The study focused on the curriculum statement', delivery' and enactment' of four lessons on the simplification of algebraic expressions, each followed by a test' question given to a mixed ability sample group from the class. It was discovered that the very generally stated curriculum was differently implemented in the textbook and by the teacher, which produced unnecessary conceptual and terminological confusion. When students received no help from the teacher, they drew upon their prior arithmetic knowledge. Upon probing, it was found that due to situational constraints, the teacher was herself unclear about the symbolic property of algebraic signs and procedures. A proper understanding of and distinction between operational symbols and quantity symbols was missing. Besides, the bilingual terminology, duplication was found to be an important complicating factor. Addressing the teacher's understanding of algebraic concepts can help reduce the gaps between the stated curriculum and the enacted curriculum. The research findings underlie the need for re-sequencing the curriculum objectives and textbook topics.