Kristin's Journal Entry

February 26, 2010

Today in class we learned about a negative in front of a bracket and adding and subtracting polynomials.

eg. 55x + 30 - (22x + 20) you can't leave it this way so it becomes: 55x +30 -22x - 20

A negative in front of a bracket means: the opposite of everything in the bracket.

Why? -( means -1 multiplying everything inside the bracket

Adding polynomials

- use models

(3x -4) + (2x +5) = 5x + 1- use symbols

(3x + 4) + (2x + 5)

=3x + 2x - 4 + 5

= 5x + 1

Subtracting polynomials

-use models

- add the opposite
(3x - 4) - (2x + 3)
= (3x - 4) + (-2x - 3)
= 3x - 2x -4 - 3
= x - 7

Scribe Post for Friday March 19

Hey 9 -05! Today we basically just corrected our tests. Here are some of the questions that most people had trouble with.

(I'm not completely sure if these are the right ones, so if they aren't, please let me know)

19. Write a simplified expression for the area of this figure. What is the area of the figure?

A = 5y (7y - 4) multiply 5y by 7y and -4

5y (7y) = 35y^2 (y^2 means y squared)

5y (-4) = -20y

= 35y^2 - 20y

The area of the figure is 35y^2 - 20y square units. « simple sentence answer

20. Apply the distributive property to simplify 2x (x-4) - 3x (x - 4).

2x (x-4) -3x (x-4)
=2x^2 - 8x - 3x^2 + 12x remember that it's -3x (x-4). Multiply 2x(x-4) and -3x (x-4)
=2x^2 - 3x^2 - 8x + 12x then you combine like terms
=-x^2 + 4x

21. A pool table is twice as long as it is wide. If the area of the pool table is 2.88m^2, what are the dimensions of the table?

I find it helpful to draw a diagram

A = lw

2.88 = 2w(w)

2.88 = 2w^2

2.88/2 = 2w^2/2

1.44 = w^2

then you find the square root

1.2 = w

The length is 2 times the width

l = 2w The dimensions are length = 2.4m and width = 1.2m.

l = 2 (1.2)

l = 2.4

We also went over these two questions.

(x + 5)^2 = (x +5) (x+5)

= x^2 +5x + 5x +25

= x^2 +10x + 25

2. 3(x+2)^2 = 3 (x+2) (x + 2)

= (3x + 6) (x+2)

= 3x^2 + 6x + 6x + 12

= 3x^2 + 12x + 12

Homework:

Get ready Chapter 6

go to www.mathplayground.com and play "zogs"

Well, that's all for my scribe. If I missed anything, please let me know. PLEASE COMMENT! (also, I have no idea who hasn't done a scribe yet, so if you haven't, YOU'RE NEXT :P) Okay, bye.

Spin A Win - Shaneille and Kristin

Spin A Win

~Rules~

Object:Get to the end of the board ( number 20) to win

Playing the Game:

1. Spin the spinner-Each number is divided into 2 sections. The coloured section is positive( remember your number)

2.Spin again -the non-coloured spaces are negative

3. Add the two together, to make a positive or negative number. The sum is the number of spaces you move. If you on 1 and you get a negative number you stay where you are.

Question Marks ??

If you land on a question mark, your partner gets to ask you a question. If you get it wrong nothing happens. If you get it right, move forward the amount of spaces on the card.

Spaces Marked X

If you land on an X, your partner gets to ask you a question. Get it wrong, you miss a turn. Get it right, you stay where you are.

Winning

First Person to Reach the the 20th space wins!

There are the rules for Spin A Win!

Scribe Post for January 4, 2010

Hey, welcome back the Class! A new year is here. Let`s all aim to do our best and keep being the Class :)

Today was basically a work period. First day back and there`s already so much work to be done.

Old Work: things assigned before the break.
Chapter 3 Get Ready (in our Work Book)
3 point approach - base
exponential form
power
difference between (-5)x and -5x (the x`s are the exponents)
coefficient
Foldable (shown on page 90 of our text book)

New Work: things that were assigned today.
Chapter 3 Math
Link Introduction (sheet)
3.1 Self Assessment
Chapter 3- read pages 88 to 96
- do the CYU

Well, that`s all the work. Just so there`s no confusion, there is
NO TEST TOMORROW! Don`t you feel so much more relieved now?

Anyway, we`re back at school so do your homework. Thanks for reading my scribe (you`re all good people)! For the next scribe, I pick Zerlina.

For Mr. Backe

Hi Mr. Backe! I hope you are enjoying your holidays. We all miss you very much. You can tell because we're all making a post saying how much we miss you. You know people like you when they blog about it.


I miss you TTTTTTTTTHHHHHHHHHHIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIISSSSSSSSSSSSSSSS
much. Math just isn't the same without you ^-^. Well, we barely did any math, but it still wasn't the same. Anyway, I know things may be, different this year, but I hope we can hear you joking around once again. I know we all miss your jokes

Well sorry there's no picture (let's just focus on the care that went into this post). Well I wish you a merry christmaaaaaasss, and a haaappyyyy neeewww yeeaaaarr!!! (I tried to make it sound like the song.....)

\(>_<\) \(^_^)/ (/-_-)/

Question # 17

Hi guys! So the question is:

To calculate -3/4 +(-2/ 3), Amy decided to convert the fractions to decimals and convert the decimals on a scientific calculator.
a) Explain why she had difficulty in determining the the exact answer by this method.
b) How should she calculate to get an exact answer?

a) -2/3 is a repeating decimal. That would mean she would have to round off to add the fractions together, which would not give her an exact answer. Although she could still find the decimal equivalent for -1 5/12. To do that, she would have to divide -5 by 12, and add that to -1.

-1 + (-0.41666.....) = -1.4167 (answer has been rounded)

I still wouldn't advise using this method because 5/12 is a repeating fraction, meaning we would have to round off, which would not give her an exact answer.

b) She should have just added the fractions together.
-3/4 + (-2/3) = -9/12 + (-8/12)
= -17/12
= -1 5/12

Since this fractions cannot be simplified further, we are done. Well, I think that explains everything. If you have any questions or something is wrong, or if you just want to COMMENT, please do. Thanks for reading! :)

Question #23

Hi guys! I was assigned question number 23 (as you probably already guessed). Anyways, here's the question:

One week in October in Iqaluit, Nunavut, the daily high temperatures were -4.6°C, -0.5°C, 1.2°C, 2.3°C, -1.1°C, 1.5°C, -3.0°C. What was the mean daily high temperatures for that week?



Well first, you have to know what a mean is. A mean is the sum of all the data, divided by the the number of data. Also known as the average.



1) Well, the first step is to group together the positive and the negative numbers.
2) Then add the like signs together.
3) Add the sums together.
4) Divide the sum of the data by the number of data (in this case, 7)

1) (-4.6, -0.5, -1.1, -3.0) + (+1.2, +2.3, +1.5)

2) = -9.2 + 5

3) = -4.2/7

4) = -0.6

I'm SO sorry this is late. I had so many problems with my computer :P I tried to upload a picture but..... yeah. Anyway, I hope this explains the question.
PLEASE COMMENT! :)

Rational Numbers

As you all know, our next unit is rational numbers.

Rational Numbers are numbers that can be expressed as a fraction. The denominator cannot be equal to zero.

Natural Numbers are numbers we use every day
example: 1, 2, 3, 4, 5, 6, 7, 8, 9
They are also called counting numbers.

Whole numbers are 0 and the natural numbers.

Integers are whole numbers and their opposites.
-3, -2, -1, 0, 1, 2, 3

As said earlier, rational numbers are numbers that can be expressed in fraction form. Irrational numbers cannot be expressed in fraction form.
Like PI and the square root of 3

Then there are real numbers. Real numbers are numbers we normally use, including rational and irrational numbers, fractions, decimals, and integers.

Just because I was curious, I searched up what imaginary numbers are. To put it simply, its a number that when squared gives a negative result.

Well that's all. Please be a good person and comment! But I won't hold it against you if you don't. :)

Scribe Post for October 8, 2009

Hi everyone! Today in class we were in the lab.

We went to that http://nlvm.usu.edu/en/nav/category_g_4_t_3.html (nlvm.usu.edu) site and played some games. The ones we were supposed to try were the platonic solids and the space blocks. I really liked playing in the platonic solids - duals. It looks really interesting. Though the space blocks give you more of a challenge.

Next, we went to http://www.shodor.org/interactivate/activities/ . In the geometry section, we explored surface area and volume.

We had to play around with the rectangular and

triangular prisms.

The homework today is (of course) journal, and online book:

- pg 31, CYU # 1-3

- pg 32 - 33, #5, 6, 7, and 9

- pg 34, # 13 to 19

Anyways, thanks for reading! Please feel free to comment on the awesomeness of this scribe, or if there are any mistakes :)

Why 360?

Have you ever wondered why a circle has 360 degrees? I didn't. But its interesting to learn why.

It all started with the Babylonians. You see, they used a number system with a base of 60, instead of using a base of 10 like we do. That system is called the sexagesimal system.

They realized that it took approximately 360 days for the sun to circle the earth. At least that's what they thought. We now know it takes 365.25 days for the earth to circle the sun, but that's beside the point... The Babylonian calendar had 360 days in a year, which is fairly close to 365. They divided their calendar into 360 degrees to keep track of daily passage of the sun's journey.







You know that in a full circle there are 360 degrees. But did you know that each degree is split into 60 parts, 1/60 of a degree? They are called minutes. Minutes are also split into 60 parts called seconds. Every second is 1/60 of a minute.

When you think about it, the way we measure time is also divided into 60's. 60 seconds in a minute, 60 minutes in an hour.

360 also has a lot of factors; 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, just to name a few. That makes it easier to work with.

Well, I hope you learned something form my post. Thanks for reading. Please comment :D