Mathematics for lawyers

Ask Judge Smith

Judge Layne Smith

Imagine that you have been transported back through time to your ninth-grade algebra class for a pop quiz. Ready? Good luck! 

Word Problem No. 1

Johnny has three dogs. Carl has twice as many cats. How old is Sally?

Word Problem No. 2

The blue train leaves the station traveling south, going 60 miles per hour. Simultaneously, a hummingbird flies north along a parallel track, going 27 miles per hour. How tall is Sally?  

Q. Judge Smith, I am majoring in humanities and plan to study law afterward. Do lawyers need math skills? – Sybil

A. Most lawyers I know joke that they went to law school to avoid math. The truth is that every lawyer needs to comprehend rudimentary math, and some need to master advanced math. Let’s consider a few examples.

Example No. 1

Private practice lawyers must understand math well enough to run a business. They also need to be able to track and account for funds deposited into their clients’ trust fund accounts. 

Example No. 2

Lawyers should be able to add, subtract, multiply, and divide to calculate damages, prejudgment interest, and the time value of money. 

Suppose the jury finds that Homer Simpson owes Montgomery Burns $5,000 for a breach of contract. Homer has owed Mr. Burns the money for 12 months. Assuming a prejudgment interest rate of 12 percent, the amount of prejudgment interest is $600. The lawyers and judge must be able to do the math.   

Example No. 3

Suppose the Brooklyn Bridge collapsed, killing 24 people and causing over $100 million dollars of property damage. The lawyers litigating the negligence and malpractice claims against contractors, architects, and engineers must understand math and physics well enough to prove or defend their cases.  

Example No. 4

Some litigation may involve statistics. A race discrimination case may compare the percentage of minority applicants hired to the percentage of majority applicants employed. Likewise, a gender discrimination case may contrast and quantify the salaries of similarly situated men and women employed to perform the same job. 

Lawyers use expert witnesses to prove or defend claims involving complex mathematics—think economists, physicists, actuaries, etc. Judges must understand math well enough to function as evidentiary gatekeepers to preclude “junk science” from being presented and confusing juries.  

By studying humanities, you will learn how to conduct research, think critically, and communicate clearly. However, if you can’t answer the word problems I included, study math and statistics, too. 

Q. Judge Smith, where is the county’s annex courthouse located? – Ted

A. The main courthouse at 301 S. Monroe Street is across the street from the state capitol building. The annex courthouse at 1920 Thomasville Road is between a liquor store and a medical marijuana dispensary. I’m not creative enough to make that up! 

The Honorable J. Layne Smith is a Circuit Judge and the author of the international bestselling book “Civics, Law, and Justice—How We Became U.S.” Email your questions to

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