A movable, transparent sleeve called the cursor was used to align numerals on the scales. The slide rule did not require any power source, but its precision was limited, and it was necessary to climb a learning curve to become proficient with it.

One of the most primitive calculators, the abacus, is still used in some regions of the Far East. The abacus acts as an adding machine that uses groups of beads to denote numbers.

Like the slide rule, the abacus requires no source of power. The beads are positioned in several parallel rows and can be moved up and down to denote arithmetic operations. It is said that a skilled abacus user can do some calculations just as fast as a person equipped with a battery-powered calculator.