This study aimed at investigating the effect of the suggested teaching strategy for the development of mathematical thinking skills on immediate and postponed achievement in the Engineering Unit in Space in Mathematics for Secondary School Students (Third Year Experimental Science Division). The study followed the experimental ap-proach through using systematic procedures during 2016-2017 in two secondary schools in Skikda -Algeria-. The study sample consisted of (141) students. The method of the study was an achievement test designed to measure the immediate and postponed achievement of the students. After examining the statistics using mathematical averages, standard deviations, and (2-WAY ANCOVA) on the level of (?=0.05) using SPSS, the study found out that using the new strategy resulted in a positive effects on the development of mathematical thinking skills on immediate and postponed achievement in the Engineering Unit in Space, both male and female students, to traditional teaching method.
Teaching Strategy, Mathematical Thinking Skills, Achievement, Classical Method, High School