Conversion of decimeter, centimeter and millimeter of mathematics in the third grade of primary school;

1 m = 10 decimeter = 100 cm.

1 decimeter =10cm =100mm.

1 cm =10mm.

1 and meters

The unit of length "meter" in the international system of units originated in France. 1790 In May, a special committee composed of French scientists suggested that one fortieth of the total length of the earth meridian passing through Paris should be used as the unit of length-meter, and 179 1 year was approved by the French Parliament.

In order to make a benchmark to represent the value of rice, under the leadership of French astronomers Gerliangbule and Mishin, measurements were made from Dunkirk, France to Barcelona, Spain, and from 1792 to 1799.

1799, according to the measurement results, a platinum rice bar with a short section of 3.5mm× 25mm was made, and the distance between the two ends of the bar was set as 1m, which was kept by the French archives, so it was also called "archival rice".

2, decimeter

Decimeter or dm is one of the metric units of length, and 1 decimeter is equivalent to one tenth of 1 meter. The common conversion relationship is as follows: 1 decimeter = 0.000 1 kilometer (km) = 0. 1 meter (m) = 10 centimeter (cm) = 100 millimeter (mm).

3, cm

Centimeter, unit of length; Chinese: centimeter (s), abbreviated as cm. The unit conversion of centimeters is as follows:1cm =10 mm = 0.1decimeter = 0.0 1 m = 0.0000 1 km.

4, um

Millimeter, also known as millimeter (or millimeter), is a unit of length and rainfall, and the symbol is ㎜. 1mm is equivalent to one thousandth of 1mm (this means "milli"). The decimal relation is as follows:1mm = 0.1cm = 0.01decimeter = 0.001m = 0.000001km.