Mental calculations done for hours together are tiring and as such calculating machines are used for doing multiplication, division, addition and subtraction. The most important figuring jobs where calculating machines are used are:
(a) Algebraic and differential equation.
(b) Scientific calculation and statistical work.
(c) Construction and engineering calculations.
(d) Pay roll and commission calculation.
(e) Preparation of discounted cash flows.
(f) Percentage, of increase and decrease.
(g) Cubic content calculation.