1. Addition
Solve multi-place-value sums efficiently and explain regrouping with exchanged units.
Study this lesson →Chapter 2: Addition and Subtraction
5 lessons · 1 consolidation units · review and practice examination
A complete original chapter draft aligned to published topic sequence. Study each lesson, answer its checks, and use the chapter examination to locate gaps. Internally reviewed with controls; external educator/learner validation remains outstanding.
Lessons
2. Subtraction
Solve differences with multiple exchanges, including through zeros, and check by addition.
Study this lesson →3. Other Ways to Add and Subtract — Part 1
Choose decompositions and compensation strategies and justify equivalent sums.
Study this lesson →4. Other Ways to Add and Subtract — Part 2
Use equal adjustments, counting-up and inverse relationships for efficient subtraction.
Study this lesson →5. Word Problems
Represent unknown totals and differences in multistep contexts using labeled bars or equations.
Study this lesson →Consolidation and assessment
Practice 1
Original mixed practice with worked reasoning.
Open practice →Chapter review
Cumulative chapter practice with revealable explanations
Open →Practice examination
Independent questions with separate answer key
Open →Complete solutions
Worked solutions and point information
Open →