rule of three
Origin of rule of three
Examples from the Web for rule of three
I do not require to examine on this point, as I consider it to be a rule-of-three calculation.Diary in America, Series Two|Frederick Marryat (AKA Captain Marryat)
Boys were never taught the rule-of-three until after they had learnt addition.Essays on Education and Kindred Subjects|Herbert Spencer
When it was found that he could not do decimals, he was put back to the rule-of-three, and then pronounced incurable.
It is as if we were to talk of the color of sound, or the longitude of the Rule-of-three.Prose Masterpieces from Modern Essayists|James Anthony Froude, Edward A. Freeman, William Ewart Gladstone, John Henry Newman and Leslie Stephen
A man who's seen Injin fightin' don't go much on this here West Point fightin' by rule-of-three—but that ain't here or there!Clarence|Bret Harte