Interpret division as equal grouping and equal sharing, recall related multiplication–division facts with products up to 100, and solve whole-number missing-factor problems. Divide two-, three-, and four-digit whole numbers by one-digit divisors using place-value models, partial quotients, or the standard algorithm, writing exact quotients or quotients with remainders less than the divisor. Estimate quotients using rounding or compatible numbers, check results with multiplication, and solve division situations by representing equations, interpreting remainders appropriately, and determining whether answers are reasonable.