Vocabulary: Chapter 2

Natural numbers- "counting numbers" starts at 1 and keeps going up. Ex: 1,2,3,4,5,6,7,8,9,10....

Whole numbers- whole numbers are exactly like natural numbers  except they start at zero. Ex: 0,1,2,3...

Integers- integers count numbers below zero as well (negative numbers) Ex: -3,-2,-1,0,1,2,3...

Negative numbers- are numbers that are placed to the left of zero on a number line. Ex:
                                 <-----(-3)-----(-2)-----(-1)-----0-----1-----2-----3----->

Rational numbers- a number that can be written as a fraction

Graph- to graph a number means to mark it on a number line. Ex: (look below)
           .
<-----(-3)-----(-2)-----(-1)-----(0)-----(1)-----(2)-----(3)----->

Coordinate- the coordinate of that point is the number that the mark represents. Ex: -3 is the coordinate in the figure above.

Absolute value- the amount of units a number is from 0. Ex: negative 10 is ten units away from 0 so 10 is its absolute value.

Opposites- opposites are always the same length from zero. Ex: The opposite of -6 is 6, they are both 6 away from 0

Additive inverse- when you add up opposites it will always equal 0. Ex: -6+6=0

Probability- the likeliness of something happening. Ex: if there are 8 marbles in a bag, 3 are pink, 5 are green, it is more likely if you were to pick one at random it would be green. If there are 4 green and 4 pink they are equally likely, they both have an equal chance of being chosen.

Sample space- a list of possibilities. Ex: if there is a bag of 2 marbles of each color (blue, green, and red) 6 total, green, blue, and red would be the sample space.

Odds- another way of showing chances is by using odds. Ex: the odds of drawing a blue marble out of 7, 3 being red and four being blue the odds would be 4:3, which is a ratio.

Square root- one of two equal multiples that are multiplied together like the square root of 36 is 6. that makes 36 a perfect square.

Radical sign- a radical sign is the thing that shows something is not a negative (a nonnegative) or is a principal square root.

Irrational numbers- An ongoing number that doesn't repeat. Ex: pi (3.14159......)

Real numbers- formed by a set of rational and irrational numbers together.

Completeness property- states that each point on a umber line is equal to one real number

Rational approximation- is when an irrational number is close to a rational number but they aren't equal.