Interpret division as equal sharing and equal grouping using arrays, equal-group diagrams, number lines, repeated subtraction, and multiplication inverse relationships, distinguishing the dividend, divisor, quotient, and group size. Recall exact division facts through $10 \times 10$, including divisors 2, 5, and 10, and divide two-digit numbers within 100 by one-digit divisors using place-value models, multiples of 10, and informal partial quotients without formal long division. Solve whole-number division problems and equations with missing dividends, divisors, or quotients, write and interpret remainders less than the divisor, and estimate quotients for one-digit divisors and dividends within 1,000 using compatible numbers.