>> Sean DiLeonardi: My name is Sean DiLeonardi. I am currently completing my Ph.D. in English at the University of North Carolina, where I study contemporary American literature; >>Amal Charara: My name is Amal Charara. I am from Chantilly, Virginia. I'm a graduate student at East Central University, earning my master's degree in education and library media. This summer Sean and I worked as junior fellows in the Science, Technology and Business Division on a project called "Arithmetic, Numeracy, Literacy, and Imagination." >> Sean DiLeonardi: Arithmetic, numeracy, literacy, and imagination describe a set of topics that together express our interest in examining how and why human beings count. Techniques of counting follow us everywhere, from the classroom to the counting house. Yet, much of the Library's holdings on these topics, from the 18th century to the present, remain understudied. Together, Amal and I wondered how we could best organize the Library's materials on these subjects, so that we might draw attention to some rich, untapped resources. >>Amal Charara: A primary goal of our work was to produce a research guide that would serve future initiatives at the Library of Congress. We curated a collection of materials, including textbooks, histories, and business guides on our subjects, most of which has remained undigitized, in order to compile information that might serve researchers working on a range of topics, from the history of business education to crowd science. In fact, as researchers ourselves, we had an opportunity to examine these materials more closely to explore their connections. >> Sean DiLeonardi: With my research, I looked more closely at materials related to the history of business education. Part of what drove my initial interest was discovering possible connections between the teaching of arithmetic and topics more closely associated with the humanities, such as literacy and imagination. It was with this interdisciplinary framework in mind that I began noticing that a proliferation of different techniques emerged throughout the nineteenth century to help students learn to count. What surprised me was that advocates regularly made claims that their device, or technique, would enhance mental activity, memory, or literacy skills in students, which would, in turn, prepare them for a variety of future business professions. As one textbook put it, students must develop mental math skills because, "Businessmen demand of their employees speed and accuracy." Together, these many initiatives related to education made up an entire industry of imagination, and they show us how important ideas about mental development were to the rise of practical mathematics. Practical math was the idea that arithmetic prepared students for professional life. For example, we could examine one of the oldest numeracy techniques, the word problem. Word problems had long been used to apply number skills to real-life contexts, often using illustrations or even stories. But as numerous examples from our collection demonstrate, word problems also required students to imagine themselves in different industries, from banking to agriculture to this illustration of a man estimating the amount of wood in a pile of lumber. This connection between arithmetic, imagination, and business preparation extended to many other techniques introduced into 19th-century classrooms, including flash cards, manual calculators, and perhaps most surprisingly, even poetry. Everywhere you look in our collection, the industry of imagination was booming. >>Amal Charara: Numeracy is all around us. It is entrancing how something as simple as teaching children mental math, such as determining the amount of wood in a pile of lumber, translates to the more sophisticated science of counting crowds. Counting crowds sounds like a simple task, yet it is quite arduous to complete. Inauguration crowds tend to have thousands, sometimes hundreds of thousands, of attendants, and it becomes difficult to determine the numbers. Here is where numeracy comes in. In the last two centuries, different techniques have emerged to calculate the number of people in a crowd, from photographs and grids to satellite images. If we study the Inauguration of Abraham Lincoln, it was estimated that thousands of people would attend. But how accurate can we get? How were the numbers identified? It's all a matter of calculating numbers. Looking at a photo, using a grid, scientists can calculate the number of people in each area using density. This was one of the ways it was measured in the 19th century. Numeracy plays a big role in the lives of data journalists, geographers, and demographers who research and culminate large crowds such as inaugurations. There are several approaches, or strategies, used to determine the quantities. Topography comes in handy when calculating spaces because it studies the shape of the surface of an area. For example, if an image is taken at an angle of a hill, the number of people may seem more than there actually are. Density maps are often used to determine numbers at these events which provides a more accurate calculation for events such as inaugurations, concerts, protests and so on. Density maps use dots to represent the number of people in a given area. Aerial photographs that can be taken by satellite or helicopters provide a visual of an area. From education techniques to crowd estimation, there is much to discover in the Science, Technology and Business Divisions' holdings in the history of arithmetic.