They're equally useful in translating metric to US measurements, and for learning the formulas.
convert centimeters, meters, kilometers, hectares, inches, feet, yards and acres.
convert ounces, grams, pounds and liters
convert meters, kilometers, inches, feet, yards and miles
convert grams, kilograms, tonnes, ounces, pounds and tons
convert Celsius and Fahrenheit
convert milliliters, liters, cubic meters, ounces, pints, quarts, gallons, cups and teaspoons
Hope this helps!