The study was aimed at observing the number conservation ability of EarlyChildhood (Pre-primary children) to test the Piaget’s theory of cognitivedevelopment. The major objective of the study was to investigate therelevance of curriculum with cognitive development of Early Childhood(Pre-primary) children. An empirical research design was used. All thegovernment and private Early Childhood (Pre-primary children) of KhyberPakhtunkhwa were population of the study. 240 students of pre-primarychildren were taken as a sample of the study. For data collection,observation sheets were developed. Statistical technique of chi-square wasapplied to analyze the collected data. It was found that primary schoolchildren of age 3 to 5 were not number conservers at any case. Hence itwas concluded that Early Childhood (Pre-primary children) were notfound to be number conservers which reflects that the level of numberconcepts (numeracy) given in National curriculum (Mathematics) ECE2002 (3 to 5 years) was higher than the cognitive level of Early Childhood(Pre-primary children) and hence it was not found to be suitable (withrespect to number conservancy) due to the non-conservancy of the EarlyChildhood (Pre-primary children). It is recommended that the numberconcepts (numeracy) given in National Curriculum for Mathematics ECE2002 (3 to 5 years) to be revised according to the cognitive level of EarlyChildhood (Pre-primary children). It should be reviewed on the basis ofindigenous research studies.