Convert among metric length units (kilometers, meters, centimeters, and millimeters), capacity units (kiloliters, liters, and milliliters), and mass units (kilograms, grams, and milligrams), as well as customary length (inches, feet, yards, miles), capacity (fluid ounces, cups, pints, quarts, gallons), and weight (ounces, pounds, tons), using the given whole-number, decimal, or familiar fractional relationships. Estimate and solve area and perimeter problems for rectangles, composite rectilinear figures, and other polygons, including partitioning figures, inferring missing side lengths, using square units, and distinguishing surface coverage from distance around a figure. Solve elapsed-time and multistep measurement word problems involving hours and minutes, unit conversions, whole numbers, fractions, and decimals while selecting appropriate operations and preserving units.