Maths is all around us. It's almost impossible to think of something that's made without the help of mathematics. Buildings, transport, technology, medicine, even clothes and food. Or rely on numbers, measurements and sums. The metric system is a universal way to measure many different things. But how does it work? Metres, grams and litres, all units in the metric system of measurement used widely today in countries all over the world. It's also the standard in the science community and is crucial to global industry. But centuries ago, there were a huge number of strange systems of measurement, many based on random objects and sometimes differing from one city to the next. Until in France in 1670, mathematician Gabrielle Mouton had a great idea to create a universal system of measurement. This international system of units, or metric system, defined meters for length, grams for weight and litres for volume as its basic units. To be as universal as possible, all the units were based upon standards in nature. For example, one meter measured one ten millionth of the distance between the North Pole and the equator. As time passed, it became easier to measure accurately and soon any laboratory with the right instruments could perfectly recreate metric standards. The units are very easy to work with, as metric values multiply or divide by ten, a hundred or a thousand. They are also named by using Latin prefixes. For instance, kilo is the basic unit multiplied by a thousand, while mille is the basic unit divided by the same. So a thousand meters is one kilometer, and one meter divided by one thousand is one millimeter. This makes working out sums simple. Move the decimal point to the right and the unit gets bigger. Move it to the left and it becomes smaller, adding zeros when needed. And the metric systems not just limited to weights and measurements. It also includes seconds for timing and pairs to measure electrical currents and Kelvin for temperature. The metric system makes measuring easy for billions of people. It's also created standards used in maths, science and industry around the world. Thanks, Gabriel Muto!