Description Level E Learning Objectives Building on the basic mental calculation skills developed in Level D, students learn basic subtraction up to subtracting 10, and work toward mastering mental math through continued practice of addition and subtraction. Book (Volume/Month) - Week (Session) - Learning Content E1 Book, Weeks 1-4: Understanding subtraction (subtracting smaller numbers) - Subtracting 1 (1~12)-1, Subtracting 2 (1~13)-2, Subtracting 3 (1~15)-3, Practice up to (1~15)-3, Achievement Test E2 Book, Weeks 1-4: Subtracting 4-10 - (1~15)-4, (1~15)-5, (1~15)-6, (1~15)-7, (1~15)-8, (1~15)-9, (1~15)-10, Practice up to (1~15)-10, Achievement Test E3 Book, Weeks 1-4: Subtracting from numbers 11-12, Subtracting from numbers 13-14, Subtracting from numbers 15-16, Subtracting from numbers up to 16, Comprehensive Achievement Test E4 Book, Weeks 1-4: Subtracting from numbers 17-19, Subtracting from numbers 20-22, Subtracting from numbers 23-25, Subtracting from numbers up to 25, Comprehensive Achievement Test E5 Book, Weeks 1-4: Comprehensive review of addition and subtraction (Levels C-E), Final Test