This study aimed to use curriculum-based measurements to sort out the difficulties of arithmetic operationsscreen for, mathematical ccomputations and concepts and applications learning disabilities in the third and fourth grades of basic education in the governorate of Muscat. In order toTo achieve the objectives study aimsof the thesis, the diagnostic accuracy of the interval cut off grades scores was determined identified to determine the classification levels for students in the third and fourth grades, using on the curriculum-based measurements in both mathematical operationscomputations and , mathematical concepts and mathematical applications. The study also sought to find the difference between the percentages of students exposed toat risk for learning difficulties disabilities in mathematical operationscomputations, concepts, and mathematical applicationsand mathematical concepts and applications according to the school type (governmental public / private). The study sample consisted of 406 male and female students from the third and fourth primary grades in the Governorate of Muscat. This study aimed to use curriculum-based measurements to screen for mathematical computations and concepts and applications learning disabilities in the third and fourth grades of basic education in the governorate of Muscat. The study also sought to find the difference between the percentages of students at risk for learning disabilities in mathematical computations and mathematical concepts and applications according to the school type (public / private). To achieve the study aim, the diagnostic accuracy of the cut off scores was identified to determine the classification levels for students in the third and fourth grades, using curriculum-based measurements in both mathematical computations and mathematical concepts and applications. The study sample consisted of 406 male and female students from the third and fourth grades in the Governorate of Muscat. Due to the Coronavirus pandemic (Covid-19), the curriculum-based measurements were administered twice a year to determine the cut off score and classification levels of screening (unlike previous studies that applied curriculum-based measurements three times a year for the purpose of screening). The ROC curve analysis showed the diagnostic accuracy of the 25th percentile score for identifying students at risk of learning disabilities. The analysis of the z-test also showed that there were no differences between the percentages of pupils at risk for learning disabilities in both public and private schools in curriculum-based measurements in both mathematical computations as well as mathematical concepts and applications. The analysis of the z-test also showed that there were no differences between the percentages of students at risk for learning disabilities between both males and females in curriculum-based measurements in both mathematical computations as well as mathematical concepts and applications.