# Multiplications sentence example

The method which Napier terms "Rabdologia" consists in the use of certain numerating rods for the performance of

**multiplications**and divisions.The second method, which he calls the "Promptuarium Multiplicationis" on account of its being the most expeditious of all for the performance of

**multiplications**, involves the use of a number of lamellae or little plates of metal disposed in a box.When algebra had advanced to the point where exponents were introduced, nothing would be more natural than that their utility as a means of performing

**multiplications**and divisions should be remarked; but it is one of the surprises in the history of science that logarithms were invented as an arithmetical improvement years before their connexion with exponents was known.This rule as to using brackets is not always observed, the convention sometimes adopted being that

**multiplications**or divisions are to be performed before additions or subtractions.In the course of reducing such expressions as (AB)C, (AB){C(DE)} and the like, where a chain of

**multiplications**has to be performed in a certain order, the**multiplications**may be all progressive, or all regressive, or partly, one, partly the other.AdvertisementIn 1617 he published a small work entitled Rabdologia relating to mechanical methods of performing

**multiplications**and divisions, and in the same year he died.It is evident that Wittich's prosthaphaeresis could not be a good method of practically effecting

**multiplications**unless the quantities to be multiplied were sines, on account of the labour of the interpolations.Involution is a direct process, consisting of successive

**multiplications**; the other two are inverse processes.As the table of antilogarithms is formed by successive

**multiplications**, so the logarithm of any given number is in theory found by successive divisions.In

**multiplications**or divisions of any length it is generally convenient to begin by forming a table of the first nine multiples of the multiplicand or divisor, and Napier's bones at best merely provide such a table, and in an incomplete form, for the additions of the two figures in the same parallelogram have to be performed each time the rods are used.AdvertisementIf instead of commencing with I and making successive additions of 1 we commence with any number such as 3 and make successive

**multiplications**by 3, we get a series 3, g, 27,.