Description Level D Learning Goals Building on the addition skills up to +4 mastered in Level C, this level trains children in addition of 5 through 10 and addition involving larger numbers, with the goal of developing the essential mental arithmetic skills needed for strong calculation ability. Volume (Book/Month) - Issue (Week) - Learning Content D1 Book, Weeks 1-4 Adding 5: (1~9)+5, (1~14)+5, (1~19)+5 Adding 6: (1~9)+6, (1~13)+6, (1~19)+6 Achievement Test D2 Book, Weeks 1-4 Adding 7: (1~9)+7, (1~19)+7, (1~23)+7 Adding 8: (1~9)+8, (1~19)+8, (1~22)+8 Achievement Test D3 Book, Weeks 1-4 Adding 9: (1~9)+9, (1~15)+9, (1~21)+9 Adding 10: (1~9)+10, (1~15)+10, (1~20)+10 Achievement Test D4 Book, Weeks 1-4 Comprehensive Review of Adding 5-10: Numbers up to 19 + (5~6), Numbers up to 19 + (7~8) Numbers up to 19 + (9~10), Numbers up to 19 + (5~10) Addition with Larger Numbers Achievement Test D5 Book, Weeks 1-4 Addition with Larger Numbers Addition where the sum of two numbers is 15 or less Addition where the sum of two numbers is 20 or less Addition where the sum of two numbers is 25 or less Addition where the sum of two numbers is 30 or less Addition where the sum of two numbers is 35 or less Addition where the sum of two numbers is 40 or less Comprehensive Addition Review (Level D) Final Test