[SubSailor]

Arithmetic (from Webster's, italics mine)

1 a : a branch of mathematics that deals usually with the nonnegative real numbers including sometimes the transfinite cardinals and with the application of the operations of addition, subtraction, multiplication, and division to them b : a treatise on arithmetic

[RightWhale]

I wonder if Howard Dean is reading this thread and screaming silently.

[The_Victor]

"A branch of mathematics" that specifically deals this basic numerical operations. The solution to 800mil/300mil is "math" it is also more precisely (and correctly) defined as arithmetic. Mathematics is the broader term which includes tensor/field mathematics, differetial equations, calculus, algebra, geometry, and finally arithmetic.