Description Level F Learning Objectives Building on the mental math skills developed in Level E, this level focuses on mastering written calculation through practice with vertical addition and subtraction. Book (Volume/Month) - Week (Session) - Learning Content F1 Book, Weeks 1–4: Addition up to 99 (vertical form) (Two-digit number + one-digit number, no carrying) (Two-digit number + two-digit number, no carrying) (Two-digit number + one-digit number, with carrying) (Two-digit number + two-digit number, with carrying) Achievement Test F2 Book, Weeks 1–4: Two-digit addition (with carrying in the tens place) Comprehensive review of two-digit addition Achievement Test F3 Book, Weeks 1–4: Three-digit addition (three-digit + one-digit), (three-digit + two-digit) (Three-digit + three-digit) Comprehensive review of three-digit addition Four-digit addition (four-digit + one-digit), (four-digit + two-digit), (four-digit + three-digit), (four-digit + four-digit) Comprehensive review of four-digit addition Achievement Test F4 Book, Weeks 1–4: One-digit subtraction (vertical form) Two-digit subtraction (two-digit - one-digit, no borrowing) (Two-digit - two-digit, no borrowing) (Two-digit - one-digit, with borrowing) (Two-digit - two-digit, with borrowing) Comprehensive review of two-digit subtraction Achievement Test F5 Book, Weeks 1–4: Three-digit subtraction (three-digit - one-digit), (three-digit - two-digit) (Three-digit - three-digit) Four-digit subtraction (four-digit - one-digit), (four-digit - two-digit) (Four-digit - three-digit), (four-digit - four-digit) Comprehensive review of three- and four-digit subtraction Final Test