Or is a centuries-old abacus less efficient than a new but slower solar-powered digital calculator?

Nowadays it can be used as a very advanced, yet basic digital calculator that uses beads on rows to represent numbers.

With digital calculators built into everything from checkbooks to hand-held computers, most consumers have at least one or two of them available at no cost.

In 1965, 4,000 digital calculators were sold globally.

Compared to the portable electronic digital calculators that were introduced in the early 1970s, slide rules had various advantages and disadvantages.

The spatial, manual operation of slide rules cultivates in the user an intuition for numerical relationships and scale that people who have used only digital calculators often lack.

The typical precision of a slide rule is about three significant digits, compared to many digits on digital calculators.

Scientists dote on computers and engineers fondle digital calculators, but accountants are a Victorian lot.

The use of in place of is commonplace in digital calculators today.

It was during this trip that Tramiel saw the first digital calculators, and decided that the mechanical adding machine was a dead end.