A. Definitions

number line – a line with numbers that are in a sequential order and differ by the same amount. Zero is called the origin, numbers to the left of zero are negative and numbers to the right of zero are positive.

integers – positive and negative whole numbers such as {… 3, 2, 1, 0, 1, 2, 3…}.

opposites – numbers that are the same distance from zero, but on opposite sides of zero,
such as –5 & 5 OR 7 & 7 OR ¾ & ¾.
 When opposites are added, the result is always zero.
 –a is read as the opposite of a.

absolute value – the distance a number is from zero and distance is always positive.
4 = 4, 3 = 3, 5 = 5

velocity  tells how fast an object is moving and in what direction.

speed  tells only how fast an object is moving. It is the absolute value of velocity provided the object continues to move in a constant direction.


B. Comparing and Graphing Numbers on the Number Line
 To compare two numbers on the number line, graph them and the one on the left is the smallest, the one on the right is the largest.
 Numbers go smaller to larger from left to right on the number line.
 To graph or plot a number, a darkened circle is put over that number on the number line.


