The current study explores the conceptual understanding of secondary level students in mathematics. The participants were 1320 students of 10th grade and 180 students of 11th grade randomly selected from 33 public secondary and 17 higher secondary schools of Lahore. The article describes the performance of students on six grade 1-7 level questions related to numbers, number operations, and algebra. One question was knowledge level and rest five were analysis level questions. Four questions were related to Knowledge of primary level Content and Students that required participants to analyze the error or explanations related to the problem. The other two questions were related to middle school content knowledge. The questions were adapted from Hill et. al. (2004)s instrument of Study of Instructional Improvement (SII). The success rate of students was ranging from 52.8 to 63.8 % on six questions and from 22 to 73.5 % on 15 sub-questions.