This document discusses length units and tools for measuring length. It explains: 1) The main unit for length is the meter (m), with smaller centimeters (cm) where there are 100 cm in 1 m. 2) Tools for measuring length include rulers and meter sticks. 3) Examples are given of objects measured in cm like hands and books, and those measured in m, like heights and desks. 4) Conversions are provided, such as 13m = 1300cm and 15m = 1500cm.