Table of Contents
Number line
A number line is a picture of a graduated straight line. The integers are shown as marked points evenly spaced on the number line. The line includes all real numbers, continuing forever in each direction, and also numbers not marked that are between the integers. It is used to help in teaching simple addition and subtraction, which involves negative numbers. A number line is usually represented as being horizontal. According to one custom, positive numbers always lie on the right side of zero, negative numbers always lie on the left side of zero, and arrowheads on both ends of the line are meant to suggest that the line continues indefinitely in the positive and negative directions.
Now, let us understand some terms.
Integers: The collection of the numbers, that is, ? -3, -2, -1, 0, 1, 2, 3, ?., is called integers.
Absolute value: The distance of a rational number from zero on the number line is called its absolute value.
Natural numbers: Numbers by which we can count things in nature are called natural numbers.
Whole numbers: Natural number along with zero forms a collection of whole numbers.
Let us understand number line:
- If you move towards the right from the zero mark on the number line, the value of the numbers increases. If you move towards the left from the zero mark on the number line, the value of the numbers decreases.
- A number line starting from 1 and marked 2, 3, 4, 5 at equal distances on the right side of 1 is called number line representing natural numbers.
- A number line starting from 0 and marked 1, 2, 3, 4, 5 at equal distances on the right side of 0 is called number line representing whole numbers.
- A number line with 0 marked anywhere on it with positive numbers 2, 3, 4, 5 marked on the right side of 0 at equal distances and negative numbers -1, -2, 4, 5 marked on the left side of ) is number line representing integers.
Let us consider some examples:
Example 1: Which is greater?
a) -12 and 15
b) -15 and -23
Solution:
a) 15
b) -15
Example 2: Replace * with the signs > or < in the given statements.
a) 0 * -5
b) -9 * -3
Solution:
a) >
b) <
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