Written Addition and Subtraction with Regrouping

Read, write, compose, decompose, and represent whole numbers up to 100,000 in standard, word, and expanded forms while explaining positional value.

Count forward and backward across place-value boundaries in intervals of 1, 2, 4, 8, 10, 50, and 100.

Compare and order multi-digit numbers up to 100,000 using comparison symbols, positional reasoning, and relative difference concepts.

Round multi-digit whole numbers to the nearest 10, 100, 1,000, or 10,000 and apply compatible numbers to assess calculation reasonableness.

Develop flexible mental strategies for adding and subtracting two- and three-digit numbers within 1,000.

Fluently add and subtract three-digit whole numbers using standard columnar algorithms and verify solutions with inverse operations.

Multiply one-digit whole numbers by multiples of 10 (10–90) and two-digit numbers by one-digit numbers using place-value strategies, partial products, and written methods.