A factor of a number is a number which divides it without remainder: thus, 4, 6, 8, are factors of 24, and 6 × 4, 8 × 3, 2 × 2 × 2 × 3, are several ways of decomposing 24 into factors.

The method of solving this and the following question may be shewn thus: If the number of days in which each could reap the field is given, the part which each could do in a day by himself can be found, and thence the part which all could do together; this being known, the number of days which it would take all to do the whole can be found.

A formula is a name given to any algebraical expression which is commonly used.

Or remove ciphers from the divisor; or make up the number of ciphers partly by removing from the divisor and annexing to the dividend, if there be not a sufficient number in the divisor.

These are not quite correct, but sufficiently so for every practical purpose.

The 1′ here means that the 1 is in the multiplier.

Meaning, of course, a really fractional number, such as ⅞ or ¹⁵/₁₁, not one which, though fractional in form, is whole in reality, such as ¹⁰/₅ or ²⁷/₃.

By square number I mean, a number which has a square root. Thus, 25 is a square number, but 26 is not.

The term ‘root’ is frequently used as an abbreviation of square root.

Or, more simply, add the second figure of the root to the first divisor.