Would Apple have invented the iPad if it weren’t for the WorkSlate, a tablet computer launched by Convergent Technologies in 1983 that assisted with spreadsheets but also functioned as an answering machine, calculator, alarm and more? Well, yeah, it would have, because the WorkSlate failed to catch on and vanished. But it was still a step forward and signaled the gadgets to come.

“My Computing Device,” an exhibit that opened Wednesday at the National Museum of American History, features a WorkSlate and 35 or so other mechanical and electric objects from the Smithsonian’s collection to not only show how they helped launch the digital age, but also to explain how our relationship with them evolved.

“Often when people think of what’s historic, they think of something that’s associated with a political campaign or a famous person,” says Peggy A. Kidwell, a curator in the museum’s division of medicine and science. “But the things people use in their ordinary lives are also part of history.”

The exhibit’s objects range from an 1840 teaching abacus to a 2013 pair of Google Glasses, primarily delivering an overview of the devices Americans have used to crunch numbers. Some offered calculating functions, like an early-20th-century slide rule and a Little Professor children’s calculator from the late 1970s. Others are games, like Simon, which tests your memory by having you repeat a steadily increasing sequence of tones and lights.

Here is a closer look at five objects at the heart of the exhibition.

National Museum of American History, 1400 Constitution Ave. NW; through August 2020, free.

Verea Calculating Machine (Patent Office model) 1878

This was the only invention of Ramón Verea, a man born and educated in Spain before he moved to Cuba, then to New York City, where he published a Spanish newspaper. This machine, for which Verea received a U.S. patent in 1878, was one of the first that could multiply two numbers directly. Older machines used repeated addition to do the math, so if the user wanted to multiply 3 by 2, he or she would set the machine to 3 and turn the crank twice. With Verea’s machine, that equation required only one turn of the crank. While his creation never made it into production, it marked an important advance in computing and popularized direct multiplication machines. “He was trying to invent a machine that would show that a Spaniard could invent as well as an American,” Kidwell says.

Nannie Helen Burroughs’ cash register 1904

From 1909 until her death in 1961, Nannie Helen Burroughs served as president of the National Training School for Women and Girls, which she founded for black women around the world. Burroughs used this elegant 1904 cash register (emblazoned with her name) to train students at her Northeast D.C. school, which paired vocational training with junior high and high school academics. Burroughs’ customized machine was made by the National Cash Register Company of Dayton, Ohio. The daughter of formerly enslaved people, Burroughs was born in Virginia in 1879 and graduated from what’s now Paul Laurence Dunbar High School in the District. The training school, no longer in operation, was renamed in Burroughs’ honor three years after she died, and D.C. has recognized her in another way. “There’s a Burroughs Avenue on the northeast side of D.C.,” Kidwell says, adding that Burroughs’ register represents “a little subtle thing that’s in the exhibit.”

Copy of BASIC for the Altair circa 1975

This roll of paper tape may not look like much, but it’s BASIC programming language software that was ubiquitous in personal microcomputers during the 1970s. BASIC stands for Beginners’ All-Purpose Symbolic Instruction Code, and this software powered the Altair 8800, an early microcomputer from the now defunct Micro Instrumentation and Telemetry Systems — the first such personal computer to sell in large numbers. “This [software] was one of the first products of a company called Micro-Soft,” Kidwell says, using the future tech giant’s original name. “This very humble object is the beginning of a transformation and a corporation.”

Xerox Star information system monitor 1981

In 1981, Xerox started selling systems of linked microprocessors for office use. While these devices were a “total flop,” according to Kidwell, they were among the first to use icons and offered applications for entering text, sending and receiving electronic mail, retrieving information, solving math equations, and more. And Xerox was one of the first companies to link workstations together. “It was only used within Xerox, but it had an influence on other people in Silicon Valley,” Kidwell says. “The people at Apple went to see it and were very, very impressed and decided that an icon-based interface would be the way to go.” Cheaper machines produced by competitors eventually took over the market, rendering the Star obsolete.

First-edition iPad 2011

This first-generation iPad belonged to a former museum intern who donated the tablet to the museum after she got a new iPad. Owners of Apple devices often replace their devices with newer models every year or two, unlike, say, mathematician R.C. Archibald, who bought a slide rule in the early 1900s and kept it for the rest of his career. “People throw out millions of computing devices every year and … I think that is more true now than it certainly was 50 years ago,” Kidwell says. “Mr. Archibald could have owned his slide rule for 20 years and it never did anything more or anything less.”