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26. To measure the Segment of a Circle
33. To measure the Frustum of a Pyramid or Cone
50. To measure an Eicosiedron
OF THE CHARACTERS MADE USE OP IN THIS TREATISE. = The sign of equality : as 12 pence = 1 shilling, signifies that 12 pence are equal to one shilling; and, in general, that whatever precedes it is equal to what follows.
+ The sign of Addition: as 5+5=10, that is, 5 added to 5 is equal to 10. Read 5 plus 5, or 5 more 5 equal to 10.
The sign of Subtraction : as, 12—458, that is, 12 lessened by 4 is equal to 8, or 4 from 12 and 8 remains. Read 12 minus 4, or 12 less 4 equal to 8.
* The sign of Multiplication : as 6 X5530, that is, 6 multiplied by 5 is equal to 30. Read 6 iuto 5 equal to 30.
or 5)30( The sign of Division : as 30-5=6, that is, 30 divided by 5 is equal to 6. Read 30 by 5 equal to 6. 875
Numbers placed fraction wise, do likewise denote division, the numerator 25 or upper number being the dividend, and the denominator or lower number, the
875 divisor; thus, is the same as 875--25=35.
25 :::: The sign of proportion, thus, 2:4::8:16, that is, as 2 is to 4 so is 8 to 16.
Signifies Geometrical Progression. 9-2+6=13 Shews that the difference between 2 and 9 added to 6 is equal to 13. Read 9 minus 2 plus 6 equal to 13. And that the line above (called a Vinculum) connects all the numbers over which it is drawn.
12—3+4=5 Signifies that the sum of 3 and 4 taken from !2 leaves or is equal 73 Signifies the second power, or Square.
13 Signifies the third power, or Cube:
vjen signifies any power in al, as 6/2 = square of 6; and 501"=cube of 50, &c. thus m signifies either the square or cube, or any other power. V, or
Prefixed to any number or quantity, signifies that the square root of That number is required. It Likewise (as also the character for any other root) stands for the expression of the root of that number or quantity to which it is presised. As 136=6, and V 100+30=12, and 3612=6, &c.
j, or li Prefixed to any number, signifies that the cube root of that number is required, or expressed. As 121636, and 15134-216=9, &c. or 2167* = 6, &c. Siguities any root in general. As 36]
As 36)=square root, 216,3=cube V,
abcd When several letters are set together, they are supposed to be multi-
.Note. The figure above is called the index of the power.
It is usual to write shillings at the left hand of a stroke, and pence at the ajght; thus, 1:3/4 is thirteen shillings and four pence.
Vote. The use of these characters must be perfectly understood by the pupil, as he may have occasion for them.
NEW AND COMPLETE
SYSTEM OF ARITHMETICK.
bers, and consists both in Theory and Practice. The Theory considers the nature and quality of numbers, and demonstrates the reason of practical operations. The Practice is that, which shews the method of working by numbers, so as to be most useful and expeditious for business, and is comprised under five principal or fundamental Rules, viz. Notation or NumeraTION, ADDITION, SUBTRACTION, MULTIPLICATION, and Division; the knowledge of which is so necessary, that scarcely any thing in life, aod nothing in trade can be done without it.
1. TEACHES the different value of figures by their different places, and to read or write any sym or number by these ten characters, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.-0 is called a cypher, and all the rest are called figures or digits.* The names and significations of these characters, and the origin or generation of the numbers they stand for, are as follow; 0 nothing ; 1 one, or a single thing calleri an unit; 1+1=2, (wo; 2+1=3, three ; 3+1=4, four; 4+1=5, five; 5+1=6, six; 6+1=7, seven ; 7+138, eight; 8+1=9, nine; 9+1=10. ten; which has no single character; and thus, by the continual addition of one, all numbers are generated.
2. The value of figures when alone, is called their simple value, and is invariable. Besides the simple valve, they have a local value, that is, a value which varies according to the place they stand
* 'These figures or digits were obtained from the Arabians, and were introduced into Europe in the ninth century. The Arabs probably derived the deci. mal notation from India. The sexagesimal division had previously been in gencral use in Europe. This mode of division is yet retained in a few cases, as in the division of time, where fixty minutes make an hour, fixty seconds a minute, &c. The figures are doubtless called digits from digitus, a finger, hecause conoting used to be performed on the fingers.
in when connected together. In a combination of figures, reckon ing from the right to the left, the figure in the first place represents its simple value; that in the second place, ten times its simple value, and so on ; each succeeding figure being ten lines the value of it in the place immediately preceding. There is no reason in the nature of numbers that their local value should vary according to this law. They might have been made to increase in 3, 4, 5, &c. fold, or in any other ratio. The tenfold increase is assumed because it is most convenient.
3. The values of the places are estimated according to their order: The first is denominated the place of units ; the second, tens ; the third, hundreds ; and so on, as in the table. Thus in the number—5293467; 7, in the first place signifies only seven ; 6, in the second place, signifies 6 tens, or sixty ; 4, in the third place, four lundred; 3, in the fourth place, three thousand ; 9, in the fifth place, ninety thousand ; 2, in the sixth place, two hundred th00 sand; 5, in the seventh place, is five millions; and the whole, taken together, is read thus ; five millions, two hundred and ninety three thousand, four hundred and sixty seven.
The process of Numeration may be more clearly seen by the following
Six places of figures, beginning on the right, are called a perivni, and each successive six places another period. Each period is cosidered as divided into two half periods of three figures each. These are distinguished by the comma, and the point for a period. There is an obvious reason for this division into periods, for at the begin
ning of each period, there is a new denomination of units, of which , the lens, hundreds, thousands, &c. ar numerated as in the first period.
4. A cypher, though it is of no signification itself, yet, it pos. sesses a place, and, when set on the right hand of figures, in shola numbers, increases their value in the same tenfold proportion; thus, 9 signifies only nine ; but if a cypher is placed on its right band, thus, 30, it then becomes ninety ; and, if iwo cyphers be placed on its right, thus, 900, it is nine hundred, &c.
5. To enumerate any parcel of figures, observe the following Rule.
First, commit the words at the head of the table, viz. units, tens, hundreds, &c. to memory, then, to the simple value of each figure, join the name of its place, beginning at the left hand, and reading towards the right.-More particularly-1. Place a dot under the right hand figure of the 21, 4th, 6th, 3th, &c. half periods, and the figure over such dot will, universally, have the name of thousands. -2. Place the figures, 1, 2, 3, 4, &c. as indices over the 2d, 3d, 4th, &c. period. These indices will then shew the number of times the millions are increased.--The figure under 1, bearing the name of millions, that under 2, the name of billions (or millions of millions) that under 3, trillions.
MMM Manns 6 5 4
Note 1. Billions is substituted for millions of millions : Trillions, for millions of millions of millions; Quatrillions, for millions of millions of millions of millions, and so on.
These names of periods of figures, derived from the Latin nume. rals, may be continucl withont end. They are as follows, for twenty periods, viz. Units, Millions, Billions, Trillions, Quatrill100s, Quintillions, Sextillions, Septillions, Octillions, Nonillions, Decillions, Undecillions, Duodecillions, I'redecillions, Quatuordecillions, Quindecillions, Sexdecillions, Septendecillions, Octodecillioni, Noveindecillions, Vigintillions.
15 Two hundred and seventy nine.
279 Three thousand four hundred and three. Thirty seven thousand, five hundred and fixty seven.
37567 Four hundred, one thousand and twenty cight. Nine millions, seventy two thousand and two hundred.
9072200 Fifty five millions, three hundred, nine thousand and nine. Light hundred millions, forty four thousand, and fifty five. i'wo thousand, five lundred' and forty three millions, four
2543431702 hundred and thirty one thousand, leven hundred and iwo.