Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

ARITHMETIC.

-. CHAPTER I.
. DEFINITIONS.
1. Any whole number is called an integer.

2. Any number which can be divided by 2, without a remainder, is called an even number.

3. All numbers which cannot be divided by 2, without a remainder, are called odd numbers.

4. Any number which can be produced by multiplying two or more numbers together, each of which is greater than a unit, is called a composite number. Thus, 35 is a compos. ite number, since it can be produced by multiplying 5 and 7 together.

5. The numbers which are multiplied together to produce a composite number, are called factors. Thus, 3 and 8 are factors of 24; so also are 4 and 6.

6. A composite number which is composed of two equal factors, is called a square number. Thus, 4, 9, 16, and 49, are square numbers.

7. A composite number which is composed of three equal factors, is called a cube number. Thus, 8, 27, and 64, are cube numbers.

8. One of the equal factors which compose a square num. ber, is called the square root of the number. Thus, 7 is called the square root of 49.

9. One of the equal factors which compose a cube number is called the cube root of the number. Thus, 3 is the cube root of 27.

10. All numbers which are not composite, are called prime numbers. Thus, 1, 2, 3, 5, 7, 11, and 13, are prime numbers.

11. Unity divided by a number is the reciprocal of that number.

SYMBOLS., 2. The symbol, =, is called the sign of equality; and denotes that the quantities between which it is placed are equal or equivalent to each other. Thus, $1=100 cents, which is read, one dollar equals one hundred cents.

2. The symbol, t, is called plus; and denotes that the quantities between which it is placed are to be added togeth. er. Thus, 6+2=8, which is read, six and two added equals eight.

3. The symbol, -, is called minus ; and denotes that the quantity which is placed at the right of it is to be subtracted from the quantity on the left. Thus, 6-2=4, which is read, six diminished by two equals four.

4. The symbol, X, is called the sign of multiplication ; and denotes that the quantities between which it is placed are to be multiplied together. Thus, 6X2=12, which is read, six multiplied by two equals twelve.

5. The symbol, -, is called the sign of division; and denotes that the quantity on the left of it is to be divided by the quantity on the right. Thus, 62=3, which is read, six divided by two equals three.

« ΠροηγούμενηΣυνέχεια »