- nate Numbers; as, dollars, pounds, shillings, pounds Dk.wrightz. ounces; hours, minutes, etc.

8; Wher different denominations of either kind form but one number, it is called a Compound Number; as, £4 3s. 62., 2 lb. 1 oz. 3 pwt. and 2 gr.

9. Numbers of the same order and the same denomination are termed Like Numbers; other numbers are termed Unlike Numbers.

REM.-Numbers expressing different species of the same genus are unlike, as horses and cows; while the same numbers expressed in the term of the genus are alike, as animals.

MATHEMATICAL TERMS USED IN ARITH

METIC. 1. An affirmative sentence, or anything proposed for consideration, is a Proposition.

2. A self-evident proposition is called an Axiom.

3. A proposition made evident by a demonstration is called a Theorem.

4. When a proposition is used for developing a principle of Arithmetic, it is called a Problem.

5. Propositions given merely for solution, in order to impress the principles on the mind, are called Examples.

6. An obvious consequence of one or more propositions is called a Corollary.

hy. An established custom, or an assumption without proof, is called a Postulate.

REM. 1 and 1 are 2, 2 and 1 are 3, 3 and 1 are 4, 5 and 2 are 7, 6 and 3 are 9, etc., is the postulate which forms the basis of Arith. AXIOMS.

1. If equal numbers are added to equal numbers, the sums will be equal.

2. If equal numbers are subtracted from equal numbers, the remainders will be equal.

3. If equals be multiplied by equals, the products will be equal.

4. If equals be divided by equals, the quotients will be equal.

5. If two numbers are each equal to the same number, they are equal to each other.

6. If the same number be added to and subtracted from another number, the latter number will not be changed.

hy. If a number be both multiplied and divided by the same number, the former number will not be changed.

8. If two numbers be equally increased or diminished, the difference of the resulting numbers will be the same as the difference of the originals.

9. If two numbers are like parts of equal numbers, they are equal to each other.

10. The whole is greater than any of its parts. 11. The whole is equal to the sum of all its parts.

SIGNS.

1. The sign t, called plus, is the sign of addition, and indicates that the number on the right hand is to le added to the one on the left.

2. The sign

-, called minus, is the sign of subtraction, and indicates that the number on the right is to be subtracted from that on the left.

3. The sign X, called into, is the sign of multipli. cation, and indicates that the numbers between which it is placed are factors of the same product.

4. The sign :, divided by, the left-hand number to be divided by the right hand.

5. The sign =, equal to, indicates that the numbers between which it is placed are equal.

6. 52, 53, the 2 and 3 placed to the right, a little above a number, indicates the power to which it is to be raised.

ry V, , indicate the extraction of the square and the cube root.

NOTATION AND NUMERATION.

1st. A figure standing alone, as 1, 2, 3, holds the units place, or is of the 1st order, and is read, one, two, three.

2d. A number having two figures, as 14, 26, the righthand figure holds the units place, and the left-hand figure that of tens, and they are read, fourteen, twenty-six.

COR.—The right-hand figure of a number is called units, or the 1st order; the next figure to the left is called tens, or the 2d order; the third figure, hundreds, or the 3d order; the fourth figure, thousands, or the 4th order; and if a number be expressed with the nine figures in order, making 1 the right-hand figure, the figures will express their respective orders ; thus,

millions, thousands, units.

co hundreds of
oo tens of
ad units of

on hundreds of
or tens of
ho units of

co hundreds of Utens of

units of

one.

9 8 7 6 5 4 3 2 1 If pointed in periods of three figures each, they may be read as follows: Nine hundred and eighty-seven millions six hundred and fifty-four thousand three hundred and twenty-one,

REM.—The figures designate the orders.
Read the following numbers:

1
21

twenty-one. 321

three hundred and twenty-one. 4,321

four thousand three bundred and twenty-one. 54,321

fifty-four thousand three hundred and twenty-one. 654,321

six bundred and fifty-four thousand three hundred and twenty-one. 7,654,321

seven millions six hundred and fifty-four thousand three hundred and twenty-one. 87,654,321 { eighty-seven millions

six hundred and fifty-four thousand three hundred and twenty-one. 987,654,321 { nine hundred and eighty-seven millions

six hundred and fifty-four thousand three kundred and twenty-one, REM.—The column of 1's is of the 1st order, the column of 2's is of the ad order, the 3's the 3d order, the 4's the 4th order, etc.

COR.–The relation of any two consecutive orders is the same, for when in addition the sum of any column reaches 10, the lefthand figure belongs to the next column or order; hence, a table may be formed, thus, 10 units

= 1 ten. 10 tens

= 1 hundred. 10 hundred

= 1 thousand.
10 thousand

= 1 ten-thousand.
10 ten-thousand = 1 hundred-thousand.
10 hundred-thousand = 1 million.
etc.

etc.

This method of numeration may be extended; thus,

Unite.

Septillions.
Sextillions.
Quintillions.
Quadrillions.
Trillions.

Billions.
Hundreds of

Tens of
co Units of
HA Hundreds of
er Tens of
. Units of
a Hundreds of
0 Tens of
c Units of

Hundreds of

Tens of
co Units of
A Hundreds of
or Tens of
o Units of
az Hundreds of

Tens of
Units of

Millions.

Thousands.
Hundreds of

Tens of
w Units of
HA Hundreds of

Tens of
os Units of

- Hundreds of
0 Tens of
co Units of

133, 456,789,123,45 6,789,123, 456,789