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A 'Treatise of Algebra.

Quantities upon each other, whose Signification the Be-ginner ought to understand.

Of the Signification os Signs.

The Sign -j- signifies that the Quantity to -which it fsprefix'd is to be added: Thus a b shews that the Quan-tity represented by b is to be added to that representedby a ; or, which comes to the fame thing, a -j- b denotesthe Quantity that arises by adding the two Quantitiese and b together ; so that if a was 3 and b 5 then woulda-\-b stand tor 3 5 or 3 . In like manner a -)- b -j- c

represents the Quantity which arises by adding all thethree Quantities a, b and c together.

Note. A Quantity which has no prefix’d Sign (as theleading Quantity a in these Examples) is always under-stood to have the Sign -}- before it.

The Sign — fignifies that the Quantity to which it is pre-fix'd is to be subtraiied: Thus a—b denotes that theQuantity represented by b is to be subtracted from thatrepresented by a, and expresses the Difference betweena and b •, as if a was 6 and b 2, then a — b would be6 — 2, or 4. Likewise afi-b — c — d stands for theQuantity which arises by taking both the Quantities cand d from the Sum of the other two Quantities a and/>; as if a was 7, b 6, c 5, and d 3, then would afi-b— c — d be 7-f-d — 5 — 3 or 5.

The Notes and — are usually expressed by theWords plus (or more) and minus (or less). Thus weread a -j- b, a plus b, and a — b, a minus b.

Also, those Quantities to which the Sign -j- is prefix’dare call’d affirmative , and those to which the Sign — isprefix’d, negative.

The Sign X signifies that the Quantities between whichitfiands are to be multiply'd together : Thus axb denotes,,that the Quantity a is to be multiply’d by the Quan-tity b, or the Product of the Quantities so multiply’d.And axbxc expresses the Product which arises bv mul-tiplying the three Quantities «, b and c continually to-gether.

Moreover