... a number line might be used to compute 4 × 3. Later, students can use open number lines (number lines on which only significant numbers areindicated) to show multiplication with larger numbers. ... whole numbers by two-digit wholenumbers, using estimation,student-generated algorithms,and standard algorithms;• multiply decimal numbers by10, 100, 1000, and 10 000, anddivide decimal numbers ... strategies;• multiply whole numbers by10, 100, and 1000, and dividewhole numbers by 10 and 100,using mental strategies;• multiply two-digit whole numbers by one-digit wholenumbers, using a variety...