In math books, cm usually stands for "centimeter". Centimeter is a unit of length, which is often used to measure length, width and height. In the International System of Units (SI), 1 cm is equal to 0.0 1 m, while in English units, 1 inch is equal to 54 cm.

When measuring length, width and height, we need to pay attention to some matters. First of all, we should choose suitable measuring tools, such as tape measure, protractor and measuring cup. Secondly, it is necessary to ensure the precision and accuracy of measuring tools. Finally, the measurement results should be verified and compared to ensure the accuracy of the measurement.

Centimeters can also be used to calculate in mathematics. For example, to calculate the surface area of a cuboid, it is necessary to measure its length, width and height first, and then use the formula to calculate: surface area =2× (length× width+length× height+width× height). When calculating, it is necessary to convert the measurement results into centimeters and carry out corresponding mathematical operations.