A very common error in the government of prepositions turned up in a book title

A very common error in the government of prepositions turned up in a book title. It is usually met with in the formatting of time intervals, but ordinarily in humdrum circumstances: in notices of opening hours, in announcements and in regulations of every sort, drawn up in haste and without any regard for grammar.

You understand, it is impossible to say «from the 4-20th century»; one may say only «from the 4th to the 20th century», or simply «in the period of the 4th-20th centuries».

If a time interval is formatted with a preposition, then the prepositions must appear in all its parts. That is, the correct forms are «children aged from 5 to 7 years are admitted to the first class» and «ready certificates are issued from 12 to 18 hours», and not «from 5-7 years» or «from 12-18 hours». Otherwise, do you see how the logic of the syntax is violated, and how the meaning of the interval is simply altered? With an interval formatted incorrectly, children will be admitted to the first class at 8 and at 9 as well, and the certificates will start to be issued when the office is already closed, do you follow?

The dash is used in intervals only if the interval is formatted entirely without prepositions, or if the preposition relates not to the first value of the span but to the whole span, for example: «the office is closed from 18-30» or «at 9-10 years old he learned to swim».

Let us commit it to memory. Correct: «at a temperature of from 180 to 200 degrees», not «from 180-200 degrees»; correct: «an income of from thirty to a hundred thousand», not «from thirty-a hundred thousand»; correct: «working hours from 10 to 18», not «from 10-18»; correct: «a mark of 4 is given for finding from 2 to 4 errors», not «from 2-4 errors».