Using math expressions in Blender input

Blender has a very convenient feature - when performing any action, the values for it can be specified in the form of expressions. For example, when rotating a mesh around the Y axis by 36 degrees, we can specify the final, already known value of the degrees of rotation and press the following key combination: R -> Y -> 36. Or, if we need to rotate the mesh by 1/5 of 180 degrees, we can use the expression by entering: R -> Y -> 180 / 5, which will be equivalent to rotating by the same 36 degrees.

Read more: https://b3d.interplanety.org/en/using-math-expressions-in-blender-input/