1 is the first positive number on the number line.
An infinite number
A number line is composed of numbers in sequential order from a number A to a number B. For example, 1 2 3 4 5 would be a number line, if the numbers were arranged on a line with small "ticks" in order to define them. 5 4 3 2 1 would also be a number line, in a negative manner. Anything on the left of a number line is considered negative, anything on the right of a number line and the number 0 is considered positive.
Integers are positive and/or negative numbers. Fractions are not integers because they are not originally positive or negative. However, they can both be put on a number line and be considered an integer. Fractions aren't integers unless put on a number line. Integers don't have to be on a number line to be considered an integer.
Yes, it is considered a number. In the past, people had difficulties accepting zero as a number, but nowadays it is universally accepted as such.
Friday the 13th is considered to be unlucky because the number 13 is considered to be an unlucky number. 13 is considered to be an unlucky number because many people are superstitious.
Party line number is to chat to people
To help people differentiate it from the number one (1).
A line dance is a dance with a repeated sequence of steps in which a number of people dance in different groups or a line of people. It doesn't matter of which gender or who the people you dancing with.
It is useful for people who are learning arithmetic or those who have not mastered it. It enables them to do simple sums. For people who have basic numeracy a number line has little to offer.
No you can not. That would be considered identity theft.