The meaning "a trouble" is mid-15c. Mathematical perception of "proposition requiring some operation to be performed" is from 1560s in English. Difficulty little one, a person by which difficulties of a private or social character are manifested, is recorded by 1916. Krebs was unable to replicate this behavior on older https://pouzdro10864.activosblog.com/26366694/manual-article-review-is-required-for-this-article