Mean Median Mode Range

These all have to do with data. Mean, median, mode, have to do with the central tendency....think of the average or middle of a group of numbers.Mean is an average found by adding up the numbers in a collection of data. Then dividing by how many you added. Example:

1+2 +3 +4 +5 = 15

Then divide 15 by 5 as in 15/5 and the

answer is three.

Median is the exact middle of a number after they are put in order. For instance in the group; 22 33 44 55 57 68 70 74. The middle is between 55 and 57. Logically you know that would be 56, but if you didn't know you could add 55 and 57 = 102. Then divide it in half and you would get 56.

Mode is the number that occurs the most in a collection of data. Example

23 44 56 34 23 34 23 The mode would be 23 because it occurred the most. Sometimes there is no mode. Sometimes there are more than one.

Range is the difference between the highest number and the lowest. Picture the mountain range with the high peaks and the low valleys.

Remember H - L In the group above, the highest was 56, the lowest was 23 so the difference would be 33.

10 100 1000 strategies link

Cast your vote!

Sports statisticians and broadcasters use so many mathematical calculations based upon ratios that are turned into decimals or percents.

Consider the baseball player that comes up to bat. Let's say it is the beginning of the season, the first game,he is one for three. He has had one hit out of three at

bats. The ratio is 1/3 . Divide three into 1.00 and the result (quotient) is .333. Remember the denominator is the divisor that goes into the numerator. The answer to a division problem is a quotient.

Notice that a diameter goes all the way from one end to the other and through the center. while a radius goes from the

edge of a circle to the center. Both are used in finding either the circumference (the distance around the circle) or area (the total inside in sq. units)

CIRCUMFERENCE = pi x d (PI IS 3.14 AND D IS DIAMETER)

Area of a circle is = pi x r x r (3.14 times radius squared)

15 5 2

3 1 10

4

20

Factors of 15 both Factors of 20

This is a picture of a Venn diagram showing how factors of

15 and 20 share the factors of 5 and 1.

Venn Diagram--named after the great mathematician John Venn . He loved logic and probability.

Factors are numbers that when multiplied together give you another number. Numbers made up of only one and itself are considered **prime**. Numbers made of of more than that are called **composite**. A man named Erastosthenes came up with a sieve to sort these way back there in Ancient Greece. (He also discovered the circumference of the earth.) You can find this Sieve in your math book p 105.

20

4 x 5

2 x 2 x 5 = 20 Do you see a 4, a 10 and the 20 all in this line?

This is a factor tree showing first a composite number of 20

Then two factors

of 4x5 then the

prime factors which end the tree.

Notice how you could make 2 x 10 from the prime factors which also equals 20!

Factor Trees help find the greatest common factor of two numbers.

16

4 x 4

2 x 2 x 2 x 2 = Two to the fourth

power

If you look at the bottom of this tree you can see that compared to the factor tree of 20, they both share a 2 x 2 which makes four. So the greatest common factor of 16 and 20 is four!

Now that we have a fraction of 4/5 we can easily change that to a decimal, then a percent.

_________

Divide 5 ) 4.00

Can you see that the quotient would be .80 ?

Multiply .80 X 100 to change it to a percent

That is equal to 80%

Or there is another way to do that by changing that fraction!

Start again with 4 x 2 8

=

5 x 2 10

Notice how 4/5 changed to eight tenths. Could you easily write the decimal of 8/10 as .8 ?

Once you have .8 , times it by 100 and you get 80%

Think of other denominators that easily change to

a 10 100 or 1000 .

Let's make a table of that!

Denominator x by = denominator

2 2 x 5 = 10

4 x 25 = 100

5 x 2 = 10

20 x 5 = 100

So if you had a fraction like 3/4 you would multiply

both the numerator and the denominator by 25 to get 75/100 = .75 and that x 100 = 75%

How is that for cool!

T**o balance and equation, there is one very important rule:**

It is important to keep it in balance.

Let us start with a simple equation of x + 3 = 14

Get the x alone by getting rid of the +3

Use the opposite operation of -3 - 3 -3

X = 11

Subtract three from both sides of the = sign

Then check the equation. If X = 11 as we said, then it must be true that 11 + 3 = 14

Yes, it is.

Now try 12 + x = 22

Solve by doing the opposite

operation -12 -12

x = 10

Check: 12 + 10 = 22 Yes, it does

So if adding and subtracting are opposite operations. What would the opposite of divide be.......

If you said multiply you are correct.

So try this **3x = 24**

The opposite of multiply by 3 is

to divide so divide both sides

of the equation by 3 3x = 24

___ ____

3) 3x 3) 24

This leaves 3 into 3 and 3 into 24 as 1x = 8

Vocabulary

Key to Math

Language

9 8 7 6 5 4 3 2 1 0 -1 -2 -3 - 4 -5 -6 7 8

A look at positive and negative integers on a number line.

One way to do work on integers is to make use of a number line

To **add **positive go to the right....

-4 + 2 = -2

Place a mark on -4 move to the right 2 and you are on -2. To **add a negative** go left.

3 + -6 = -3

To subtract integers remember this rule. Subtracting an integer is the same as adding its opposite.

So -100**-** -75= -25

In multiplying integers remember the product of two integers with different signs is always negative.

-7 x +3 = -21

The product of integers with same signs is always positive.

If one is zero, the product is 0.

In dividing integers remember the quotient of two integers with the same sign is always positive +45/+9= +5 and

-72 /-8 = + 9

The quotient of two integers with different signs is always negative.

36 /-9 = -4

. . . . . . . . . . . . . .

Chapter 1: base of a power, exponent, power of 10, period, equivalent, standard form, word form, short word form, expanded form, decimals, digit, rounding numbers,sum, difference, product, quotient, divisor, metric measurement

Chapter 2:**mean, median, mode, range, **frequency table, histogram, data set, measures of central tendency cluster, gap , outlier, stm and leaf plot, box and whisker plot, quartile, extreme, bar graph, double bar graph, double line graph, pictograph,

Chapter 3:**composite number, factor,** improper fraction,multiple, ratio, decimal, percent, fraction, numerator, dividend, denominator, divisor, prime factorization, greatest common factor, greatest common divisor, least common multiple, equivalent fractions, simplest form, common denominator, least common denominator,repeating decimal, terminating decimal, rules of divisibility,**venn diagram** factor tree, greatest common factor,

Chapter 4 improper fraction, mixed number, reciprocal, invert, customary measures,cenral angles

Chapter 5 absolute value, integers, negative integer oppostie inumbers, positive integer, rational number , additive inverse

Chapter 6 associative property, commutative property, distributive property, identity property, reciprocal, zero property, evaluate, algebraic, expression, inverse operations, variable, order of operations

Chapter 7 ratio, rate ,equivalent ratios, proportion, scale, scale drawing

Chapter 8: rate, base, percentage, principal, interest rate,simple interest, discount

Chapter 9: Geometry Terms:plane, transformation, translation, rotation, reflexion, point , line, ray,

line segment, triangle, acute triangle, scalene triangle, obtuse triangle, equilateral triangle, isosceles triangle, angle, straight anlgle, right angle, obtuse angle, acute angle, complementary, supplementary anlgels,vertical angles, adjacent angles, interior of an angle, regular polygon, congruent, corresponding parts, diagonal, scale, quadrilateral, square, rectangle, pentagon, hexagon, chord, arc, collinear, noncollinear, protractor, diameter, radius, parallelogram, trapezoid, rhombus,

Chapter 10

perimeter, area, circumference pi, prism, pyramid, solid figure, cylinder, cone, net, surface area, volume

Chapter 11 data, outcome, probability, statistics, tree diagram, sample, biased sample, random sample, fundamental counting principal, experimental probability dependent events, survey disjoint events, population, experiment, event, theoretical probability, experimental probability, sample space., compound event, independent event

Chapter 12 linear equation, quadrant, cooridinate plane, origin, ordered pair, function, x-coordinate y-coordinate

Factors are = or less than the number you are factoring!