Demvry's Algebra Post

Algebra - writing mathematical phrases using letters to represent numbers

Variable - the unknown
- use a letter to represent a number

Constant - the integer in an algebraic expression or equation

Solving One-Step Equation
1) Isolate the variable
2) Cancel using the opposite
- Create a zero pair for the CONSTANT
3) Balance on the other side of the equal sign
4) Verify your answer

Ex. n + 6 = 14



Solving One-Step Equation Video


Links:
http://www.algebralab.org/lessons/lesson.aspx?file=Algebra_OneVariableOneStep.xml
http://staff.argyll.epsb.ca/jreed/math8/strand2/2202.htm
http://www.algebra-class.com/one-step-equations.html

Solving Two-Step Equation
1) Isolate the variable
2) Cancel the constant
3) Balance
4) Simplify the variable
5) Balance
6) Verify

Ex. 2x + 4 = 10



Solving Two-Step Equation Video


Links:
http://www.math.com/school/subject2/lessons/S2U3L6GL.html
http://www.numberpower.org/BeyondBasics/Algebra/HTML/2StepEquatiBasic.html
http://www.mathguide.com/lessons/Equations.html

Volume Post

Textbook

Chapter 7.3
4.
a)

v = π.r.r.h
v = (3.14x5x5) x 23
v = 78.5 x 23
v = 1805.5cm3


b)

v = π.r.r.h
v = (3.14x14) x 12
v = 615.44 x 12
v = 7385.28cm3


c)

v = π.r.r.h
v = (3.14x0.5x0.5) x 1.5
v = 0.785 x 1.5
v = 1.1775m3


Chapter 7.4
3.
a)

v = (bxh÷2) x h2
v = (1.4x1.7÷2) x 1.7
v = 1.19 x 1.7
v = 2.023m3

Link
http://www.math.com/tables/geometry/volumes.htm

Video

Term 2 Reflection

Term 2 Reflection

In term 2, I believe I did good on the nets of three-dimensional objects, the volume of the cylinder(π.R.R.H [Pi-3.14 x radius x radius x height]), the surface area of a prism(A=LxW [area=length x width]), and the volume of the rectangular prism(LxWxH [length x width x height]).

What made me struggle was remembering all the formulas on the volumes but in the end I was able to remember the 3 formulas.

For next term, I will try to stay focus and try to catch up on any home work that I miss. Also, I will try to get my marks up and my grades higher. Lastly, I will try to ignore the distractions throughout the grades.

What I learned about percents is that I can combine and compare percents. Also, what I learned about the surface area is that the surface area is the sum of all the areas and that it determines the surface area and volume of three-dimensional objects. Lastly, the volume. The volume is measured in "cubic" units. The volume of a figure is the number of cubes needed to fill it completely, like blocks in a box.

The difference between the surface area and the volume is that the surface area would be measured in square inches. The area of a flat surface, like a desk top. The volume is the inside area, like inside a balloon. This would be measured in cubic inches (inches x inches x inches).


I will try to add an audioboo sooner or later

Demvry's Great Big Book Of Integers

Chapter 1 Grade 7 Integer Review

(+4) + (-2) = +2
Positive 4 and Negative 2 have 4 and owes 2 which is now 2+
Standard Form: 4 - 2 = 2
Making Zero Pairs:
-16 = +16
-5 = +5
+6 = -6
-2 = +2
-10 = +10
+3 = -3
+11 = -11
-9 = +9

Chapter 2 Multiplying Intergers

Sign Rule (Negative signs)
Even = When you have an even number of NEGATIVE factors, the product is POSITIVE
Odd = When you have an odd number of NEGATIVE factors the product is NEGATIVE

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

Standard form
(2) x (3) = 6
2(3) = 6

o
o ooo ooo = 6
(+2) x (+3) = 6
or
2 groups of (+3) = 6

o
o ooo ooo = -6
(+2) x (-3) = -6 ← remove 2 groups of (+3) ← use zero pairs -remove all
or
2 groups of (-3) = -6

o ooo ooo
o
(-2) x (-3)
↑ remove 2 groups of (-3) = +6

o oooo oooo oooo
o
(-3) x (-4) = +12

o
o oooooooo
(+2) x (+4) = +8
(+5) x (-2) = -10 (-4) x (+2) = -8 ← 4 x 2 for zero pairs ← remove (+) left with (-)
(-6) x (-1) = 6

Chapter 3 Dividing Integers

Sign Rule
If you have no NEGATIVE or an even number of NEGATIVE signs in a division question, the quotient is POSITIVE. When you have an odd number of NEGATIVE signs in a division question the quotient is NEGATIVE.

2 Types of Division:
Partitive Division or making parts
Partitive Division is making parts.
6 ÷ 2 = 3, how many groups of 2 are in 6?
oo|oo|oo ← There are 3 groups of 2 in 6

6 ÷ 2 = 3 and -6 ÷ (-2) = 3
3 groups of 2 ←↓
***→2→ →2→ →2→
←2-----------------------6→

3 groups of 2←↓
*****←2← ←2← ←2←
←(-6)-----------------------(-2)→

Quotative Division or sharing your total with groups
Quotative Division is sharing your total with groups.
-6 ÷ 3 = -2, share 6 with 3 groups
oooooo ← 6 totals
( ) ( ) ( ) ← 3 groups
(oo) (oo) (oo) ← 2 out of 6 totals are in 1 group

Chapter 4 Order of Operations with Integers

BEDMAS

Brackets
Exponents
Division
Multiplication
Addition
Subtraction

Steps:

1) Brackets (if there's a square bracket, always do that first then the round bracket)

2) Multiply and divide in order, left to right.

3) Add and subtract in order, left to right.

(+5) x (-3) + (-6) ÷ (+3) = ?

(+5) x (-3) + (-2) = -17
(-15) + (-2) = -17

(+5) x (-3) = -15
(-6) ÷ (+3) = -2
(-15) + (-2) = -17
= -17

Demvry's Textbook Homework

Pages 258-261
Questions 18 and 19

Question:
18.Suki has 30 small linking cubes.
a)She wants to use 18 of them to make a large cube. Is this possible? Why or why not?
b)What number of linking cubes would she use to construct the largest cube she can possibly make?

Answer:
a)I say this is not possible because I think there is no whole number that could be cubed to be able to equal 18.
b)She would probably need to use 27 cubes to make the largest cube possible (3x3x3).


Question:
19.Melissa has three glass vases. She wants to use one as a decorative fish tank for Harvey the guppy. Which will give Harvey the most water to swim in.

Answer:
The volume of the one shaped as a cube is 343cm2.
The volume of the one shaped as a rectangular prism is 360cm2.
The volume of the one shaped as a triangular prism is 367.5cm3.

According to the volumes, the triangular prism would've the most water for Harvey the guppy to swim in.

Here are some videos!
Volume of a cube!


Volume of a rectangular prism!


Volume of a triangular prism!


Here is a link to help you understand it better!
http://www.math.com/tables/geometry/volumes.htm

Inform me if I made a mistake or tell me what I could improve on. Thanks.
Ps - If the letters are over or undersized, ignore it and I'll try to find a way to fix it. If I can't, I'm sorry.

Demvry's Final Percent Post

~ A percent means out of 100 and it's another name for hundreths which can be represented as a decimal or fraction
~Ex. 65% means 65 out of 100 or 65/100 or 0.65

4.1 Representing Percents

Key Ideas
To represent a percent you can use 100 grid charts. One shaded grid that has all the squares shaded in represents 100%. To show a percent that is larger than 100% you shade in more than one grid. To represent a percent between 0% and 1% you shade in a part of one square.

Fractional Percent - A percent that includes a portion of a percent.
Ex. 1/2%, 0.42%, 73/8%, 125 3/4%, 4.5%

4.2 Fractions, Decimals, & Percents

Key Ideas
Fractions, decimals, and percents can be used to represent numbers in various situations.
Percents can be written as fraction as decimals.
Ex. 1/2%=0.5% 0.5%=0.5/100 =0.005
150%=150/100 =1.5 or 11/2
423/4%=42.75% 42.75%=42.75/100 =0.4275

4.3 Percent of a Number

Key Ideas
You can use mental math strageties such as halving, doubling, and dividing by ten to find the percents of some numbers.
To calculate the percent of a number, write the percent as a decimal and then multiply by the number.
Ex.121/2% of 50 = 0.125 x 50 = 6.25
121/2%=12.5 = 0.125

4.4 Combining Percents

Key Ideas
Percents can be combined by adding to solve problems. 5% + 7% = 12%
To calculate the increase in a number,
~You can add the combined percent amount to the original number: 12% of 100 =0.12 x 100 = 12 100+12=120
~You can multiply the original number by a single percent greater than 100
Percents of percents can be used to determine amounts that result from consecutive percent increases or decreases.

Demvry's Percent Review Video


The video is kinda blurry so you might not see it very well.
The ending got cut off due to my computer.

Here's a link to help you understand percents better!
http://www.mathgoodies.com/lessons/toc_vol4.html

The words might be oversized or undersized since it got lagged and became like that. If not ignore this.

Demvry's Pay It Forward

Part 1:
In my thoughts, paying it forward means doing a random act of kindness knowing that you are getting nothing in return. Doing a random act of kindness can be giving your place in line for someone in seems in a rush or opening the door for someone who seems to be loaded with bags. Doing a random act of kindness will let people recognize how to do the same thing to other people which will lead to paying it forward.

Part 2:
My pay it forward act of kindness were helping people shovel their yard, donating to The Salvation Army, and putting up flyers around Brooklands School. We chose these activities because it seems helpful and fun at the same time. We helped people to shovel their yard and helped people who are in need with the donation. We shoveled people's yard, donate to The Salvation Army, and put flyers around Brooklands School. We did out act of kindness in December 18th, 19, and the 20th.



Part 3:
It went pretty smooth but it wasn't all fully groups. Everyone did their job and stuff but in different times. I felt good inside, knowing that I did a good cause in this community. They reacted suprise to see people like us helping them clean their yard up. We didn't really ask to pay it forward since we were kind of nervous.

Part 4:
The idea of paying it forward is important because it lets people be nice to another and to do the same thing to other people which will lead to paying it forward. We think it did since it will tell people to helpout one another and be nice to eachother.

Demvry's Math Book H.W

Page's 42-43

5) The commission for the sale of a house was 63/4%. If the house sold for $345 000, how much was the commission? Show your thinking.



I divided 100 by 100 and got 1 and then I times it with 6.75 which then I ended up with 6.75%
I did the same steps as the percent as in dividing 345 000 by 100 and it got me 3450 which then I times it with 6.75 leading me to $23287.50
Sorry if it made no sense!



6) Table salt is a chemical compound of sodium and chlorine. Recommended daily intake is about 1700 mg. If Canadians consume 182% of this amount on average, how much sodium is one person eating daily?




I divided the 100% by 100 and ended up with 1%. I times that 1% by 182 and ended up with 182%.
I did the same steps as the percent and ended up with 3094 mg.
Sorry if it didn't make sense again!

Link:
http://www.worsleyschool.net/science/files/percentofa/number.html

Video:



Tell me any mistakes that I made and tell me what I could improve on :]
Thank you for your help!

Demvry's Pythagoras

H.W
Page 91-94

5) a)


b)402=1600
752=5625
852=7225

c)a2+b2=c2
402+752=852
(40x40)+(75x75)=(85x85)
16002+56252=72252
7225mm2=7225mm2

10)

a2+b2=c2
1202+1602=2002
(120x120)+(160x160)=(200x200)
144002+256002=400002
40000mm2=40000mm2

Yes,I think this is a right triangle since a2 plus b2 equals c2.
(144002+256002=400002)


15)

a2+b2=c2
62+82=102
(6x6)+(8x8)=(10x10)
362+642=1002
100cm2=100cm2

I think this is a right triangle since 362 plus 642 equals 1002

19) I couldn't think of an answer so I wasn't able to do this. So sorry!
102+152=?2
Here is a link!
http://www.historyforkids.org/learn/greeks/science/math/pythagoras.htm

Here is a video!

Demvry's Sesame Street Video

Group Members: Demvry, Nino

Part 1:

Two term ratio : Compares 2 quantities measured in the same units. (a:b)

Three term ratio : Compares 3 quantities measured in the same units. (a:b:c)

Part to part ratio : Compares different parts of a group to each other. (a:b, 2:5)
Part to whole ratio : Compares one part of the group to the whole group. It can be written as a fraction, decimal, & percent. (b:all letters, 5:8)
Rate; Compares 2 quantities measured in different units (2km/2hr)
Propertion reasoning : A relationship that says that 2 rates or ratios are equal. It can be written in fraction form. (2/3 = 6/9. (x3))

Part 2:
The Original Video:

The Martians Discover a Book

Remake:
The Martians and The Math Book

Demvry's Math Profile

Hello there, my name is Demvry. I'm a grade 8 math student. If someone would ask me if I liked math, I would say I'm not really a math person so I'll try my best to get a good grade in math. Doing math is like answering an impossible question but in the end I always learn new things about math. The best thing that ever happened to me was getting an almost perfect score in grade 7 on a test. That test was so hard that it made me worry and think that I would fail but luckily I pulled it through. I liked that event because I studied really hard and it made me very focused.

In grade 7, the best thing that I ever studied was integers because I really didn't know what it really ment until I learned it. Integers are not really hard so anyone can learn it. The circle graph was the one that made me struggle. For example the area, circumference, radius, diameter, and stuff like that really confused me. This year I'll try to get as much learnings as I can to not struggle too much.

I am now in grade 8. To be a successful student, I must do my H.Ws and focus on everything that I learn so I can do well in tests and quizes. I would like to learn new things this year so I can prove myself that I can try my best to improve.

The blogg post I posted was about BEDMAS, Here's a link about it http://www.onlinemathlearning.com/bedmas.html
Blogging helped me become a better student because it made me understand more about it at home. This year I would like to learn something new on the computer in math class. Learning new things is like exploring an unknown world.


Here's a video about my Blog.