Why go
A street number can tell you which part of Bogotá you are approaching before you arrive. Carreras generally run along the mountain edge and calles cross them. Reading the full address, including an E or S suffix, prevents confusion between streets with similar numbers.
The full story
Carreras generally run north–south, roughly parallel to Bogotá’s eastern hills. Their numbers usually increase westward, away from the mountains. Calles cross them east–west; in the northern part of the city, their numbers increase as you travel north. This makes Calle 13 a very different location from Calle 200. Suffixes change that simple pattern. An E marks an eastern carrera, while an S identifies a southern calle, where numbers increase southward. Do not drop those letters when copying an address or looking up a destination. Diagonales and transversales depart from the regular grid, so a street number alone does not establish the exact approach. In an address such as Calle 45 #24-15, Calle 45 is the street and 24 identifies the nearby crossing carrera. The final number locates the property along the block. Use this as an orientation aid, then check the full location on a map, especially where the grid bends or an avenue has another name.