Until recently, only 10 leaves of the oldest manuscript prepared by Abraham Lincoln were thought to have survived. However, Nerida Ellerton and Ken Clements, professors in Illinois State University’s Department of Mathematics, have determined that a fragment in the archives in Houghton Library at Harvard University is in fact an 11th leaf from the oldest surviving manuscript written by the future president.

The fragment, long ago separated from the other surviving 10 leaves, was featured in Houghton Library’s 2009 exhibition, “Harvard’s Lincoln.”

An associated document in Houghton Library, written by William Herndon, Lincoln’s law partner, and dated December 7, 1875, confirms that both sides of the leaf were indeed prepared by a young Abraham Lincoln. Scanned images of the manuscript pages and the Herndon letter can be found online.

The young Lincoln prepared his arithmetic manuscript—known as a cyphering book in Lincoln’s time—when attending schools in Indiana between 1820 and 1826. The Harvard University leaf was probably completed by Lincoln when he was 16 years old, late in 1825.

Guided by their knowledge of the arithmetic curriculum in U.S. schools in the early 19th century, Ellerton and Clements have been able to shed light on the ordering of the 11 leaves, and on the mathematical content of the pages. Ellerton and Clements authored the book Rewriting the History of School Mathematics in North America 1607–1861, published by Springer, a New York publisher, in 2012.

Their research on Lincoln’s oldest manuscript will be published as a chapter, coauthored with Valeria Aguirre Holguin of New Mexico State University, in a new book on extraordinary cyphering books to be published by Springer in 2014. Ellerton, Holguin and Clements’s analyses reveal that the future president’s mathematical achievements at school were greater than previously reported, and that claims that Lincoln was wrong when making certain types of calculations are incorrect.

“The solutions to the mathematics problems in Lincoln’s manuscript show that the young Abraham not only knew what he was doing, but also that he understood the mathematical principles he was applying,” said Clements and Ellerton. “Almost all of his problem solutions were correct.”

“The discovery of an 11th leaf of Lincoln’s oldest manuscript is an exciting addition to the corpus of Lincoln’s early writings,” said Daniel W. Stowell, director of the Papers of Abraham Lincoln project. “We are grateful to Drs. Ellerton and Clements both for this discovery and for their careful examination and reordering of the pages separated 150 years ago. Their expertise in the field of mathematics education sheds new light on this enigmatic document from Lincoln’s early life.”

The Papers of Abraham Lincoln will include this document among the more than 100,000 documents it expects to locate, image, transcribe, annotate, and publish online in the years ahead.

In April 2010, the Papers of Abraham Lincoln, together with the University of Chicago and Brown University, announced the electronic reuniting of two fragments from another leaf of Lincoln’s arithmetic copybook. The Collected Works of Abraham Lincoln, published in 1953, began with copies of the then known 10 leaves of this manuscript, but included only the half fragment from Brown University. The matching half page was discovered in November, 2009 at the University of Chicago.

The Papers of Abraham Lincoln is a long-term documentary editing project dedicated to identifying, imaging, transcribing, annotating, and publishing all documents written by or to Abraham Lincoln during his lifetime (1809-1865). The project is administered through the Abraham Lincoln Presidential Library and Museum, and is co-sponsored by the Center for State Policy and Leadership at the University of Illinois, Springfield, and by the Abraham Lincoln Association.

Examples of problems that Abraham Lincoln solved on the recently discovered leaf:

If 100£ in 12 months gain 7£ interest what principal will gain 3£-18S-9d in 9 months?

If the tuition of 3 boys for two quarters of a year be $40-20 cts how much will the tuition of 60 boys amount to for 4½ years?

If 4 men in 5 days eat 7 lb. of bread, how much will be sufficient for 16 men in 15 days?

If 100 dollars in one year gain 3½ dollars interest, what sum will gain $38.50 cents in one year and a quarter?