841Michael+A

Here are my math questions and explanations. If something looks wrong or doesn't work, or if i missed something, please tell me.

Here are some links to my other math work. [|B. O. B.] (Blogging on Blogger) [|Scribe Post] [|Growing Post]

__**Mean, Median, Mode -**

Mean:__ T o find the mean you add together every number in a set of data. Th en you take that sum of all data and divide it by the amount of data you have. It's also the same thing as the average. --Example-- 2, 4, 7, 9. 2+4+7+9 22.Then 22/4 **5.5**. So 5.5 is the mean of those four numbers.

__Median:__ To find the median you first put the set of data in numerical order. Then you find the middle number, then that is the median. --Example-- 3, 7, 4. -numerical order- = 3, **4**, 7. Since 4 is in the middle, it is considered to be the median.

However, if you have two middle numbers, you find the mean of those numbers. --Example-- 7, 4, 3, 1, 2, 2. -numerical order- 1, 2, **2**, **3**, 4, 7. Since 2 and 3 share the middle, you find their mean. 2+3 = 5 / 2 2.5. So 2.5 is the median.

__Mode:__ To find the mode, find the number that appears the most in a set of data.

3, 3, 4, 4, **5**, **5**, **5**. Since 5 appears the most, we say its the mode.

There can be more than one mode: Since 3 and 4 appear more than all the other numbers (in this case the one 5), they are both the mode.
 * 3**, **3**, **4**, **4**, 5.

There can also be no mode: 3, 3, 4, 4, 5, 5, Since no numbers appear more than any others, there is no mode.

Find the mean, median, and mode.
 * Question: 8, 4, 3, 3, 5, 7.**

mean: 5 median: 4.5 mode: 3

Answer

__Perfect Square:__ A whole number that has a whole square root. --Example--
 * __Square Roots__** __**-**__

25 is a perfect square because 5x5 = 25.


 * <--__On the left is a perfect square chart, showing the first nine perfect squares.__**

__Square Root:__ A number of another number that you multiply by itself to get that number. --Example-- 5 is the square root of 25 because 5x5 = 25.

__Finding the square root of a number without a calculator:__ To find the square root of, say, 21:

Step 1: Find the two nearest perfect squares. -- 4x4 **= 16**, 21, 5x5 **25** --

Step 2: Subtract the previous perfect square from the next perfect square. -- 25 - 16 = **9**. 9 will be the denominator.

Step 3: Subtract the previous perfect square from the number you are trying to find the square root of. -- 21 - 16 = **5**. 5 will be the numerator.

Step 4: The previous perfect square square root will be the whole number. -- sqrt16 =**4** (4 x 4= 16). 4 will be the whole number. Step 5: Put all the parts together.
 * 4 5/9.** So the sqrt of 21 is 4 5/9, which can be converted to about 4.5 repeating.

Find the square root of the following**
 * Question:

a)14

3 5/7

b)23

4 7/9 Answer

__**Percent:**__

To find the percent of any number.. --Example-- find 12% of 100

-- take number your trying to find the percent of and divide by 100. (100/100=1) -- then multiply that by the number you want to find. (1x12=12) -- so 12 is 12% of 100.

25% off the original price? Why or why not?**
 * Question:**
 * Is taking 15% off a given item and then an additional 10% off the reduced price the same as taking

1) $85 - 8.5 $76.5 2) $75 not the same Answer

__**Ratio/Proportion -**__

To do __ratio tables__: --Example-- If 3 chocolate bars cost $3, how much do 5 bars cost?

First you find 3's unit value (3/3=1, $3/$3 $1)

Then you multiply it by the number you're trying to find, in this case, 5. (1x5=5, $1x$5=$5)

So 5 bars cost $5.

To use __fractions:__ --Example-- If 3 chocolate bars cost $3, how much do 5 bars cost?



Just like with ratio tables, we have to find the unit value of 3. (3/3=1, $3/$3=$1)

And then we again multiply it by the amount we are trying to find. (1x5=5, $1x$5=$5)

So again, we end up with 5 bars costing $5.

Solve using both a ratio table and fractions.**
 * __Question:__ If 2 rubber balls cost $1.50, how much would 5 balls cost?

$3.75

balls/cost = 2/$1.50 = 5/$3.75

Answer