It would be difficult to overestimate the extent to which mathematics
enters into the conditions of everyday life. In its elementary stages,
as the science of number, it teaches us the relations of magnitude, and
enables us to build up a system of calculation and measurement which,
applied to the relations observed to exist in nature, gives results of
far-reaching importance.
The properties of number are investigated in arithmetic, and methods
examined by which those engaged in practical science are able to work
out their results to any degree of approximation.
With the help of algebra, we arrive at a system of logarithms by which
many of these results may be reached with the minimum of labor.
The measurement of lines and angles, by methods investigated in geometry
and trigonometry, enables us to calculate areas, and work out various
problems met with in surveying, and is of the first importance in
astronomy.
_Arithmetic_, which deals with the properties of numbers, forms the
basis of all mathematical calculation. (For the _primary_ treatment of
numbers, see under The Child World.)