Alharbi, Mohammed, and Nasser Al harbi. “The Level of Inclusion of 21st Century Skills in Mathematics Book for the Second Intermediate Grade in the Kingdom of Saudi Arabia, in Light of the Mutual Dimensions of the Education and Training Evaluation Commission.”. International Journal of research in Educational Sciences. (IJRES) 4, no. 1 (December 15, 2020): 447 -496. Accessed March 5, 2021.