The metric system is in general use around the world and if kids learn it early they will have no problem adjusting to it. The U.S. has not converted to the metric system and it tends to stand alone when it comes to temperature, weights and measures. Readers learn that Celsius is the scale for temperature and that it is written with a degree symbol followed by the letter “C.” The metric system uses a pattern of tens and there is a spread that introduces—kilo, hector, deca, deci, centi and milli with a simple example to demonstrate what each means. Mass is measured in grams and liquids in liters.