Sandra's Term 2 Reflection

Math term 2 reflection

This term in math we learned about Percent, Surface area, and Volume. We learned about representing percents by using hundred grids, fractions, decimals and percents, finding percent of a number and combining percents. I liked learning about percent, it’s a great skill to apply to real life situations, such as going shopping and finding tax of a price. I was pretty good at this unit, I improved on my quizzes from last term, although I didn’t do too well on my unit test. What I would like to work on is combining percents because it was a little hard for me, I think I should of did more textbook work too in that area.
The next unit we learned about was surface area. I understood this unit very well and I got 100% on all my quizzes including my unit test. This unit was certainly much more easier than the previous units, maybe because we didn’t do much problem solving and focused mainly on the formulas and diagrams. Overall, I really enjoyed this unit and I think I did exceptionally well.
The last unit we did was volume. Volume seemed to be even more easy than surface area at first, but when it came to the problem solving it required much more thinking. I loved volume, mostly because of the problems because I like to challenge my self to see if I am capable of solving them on my own, and relying on my brain. Allot of them I made mistakes on, but it was a great learning experience for me. I did really well on my tests and quizzes, which I am proud of. Again I really enjoyed this unit.
So that is what we learned about in term 2. I really improved this term, and I hope to improve further on in my math. I think that these units were pretty easy units and now I have to get myself prepared for the next ones that look more complicated such as fractions and integers, those units I struggled with last year but I hope I will do better now. We did blog work for term two, there was Final Percent post and video
Surface area of a Cylinder

Sandra's great big book of integers

Chapter 1

Grade 7 integer review
In grade 7, we learned about integers as being only represented as whole numbers that could be either posative or negative. We learned how to represent them by using integer chips and number lines. You can also make zero pairs with an even amount of posative integers and negative integers.

Find zero pairs for the following integers:

Integers in Grade 7
+4 is like saying you have 4 and -4 is like saying you owe 4.

In grade 7 we wrote integers using brackets ex. (+4) + (-4), these are just "training wheels", the actual standard form is written like this: +4-4 and the pure standard form is written like this: 4-4.

10-(-4) you are removing the negative part of the zero pair.

-3-2 is not subtracting, rather you have to add the negative integer.

Here are some questions:

1. -3-(-7)=+4

2.-3-7=-10




3. 3-7=-4

4.3+7=10

Chapter 2: Multiplying Integers

Here is how I multiplied these integers:




1.2x3=6























2. 2x(-3)=-6






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


4.(-2)x(-3)=+6


Chapter 3: Dividing Integers

There are two different types of division: Partative and quotative. Partative division is when you know the number of groups but what you are trying to find is the number of items in that particular group.
Ex.



1. 6/2=3






2. -6/-2=+3


Quotative Division is the oposite of partative divisiong, you have to try and find the number of groups.


Ex.





-6/2=(-3)

There are some sign rules you may need to keep in mind for multiplying and dividing integers: When you are dividing two integers that are the same, the answer will be posative. However, if you are dividing two integers that are different, the answer will be a negative integer.


Chapter 4: Order of operations with integers

(+5) x (-3) + (-6) ÷ (+3)=

When solving this problem we will have to apply the BEDMAS rules.

(+5)x(-3)+(-6)/(+3)=
(-15)+-6/(+3)=
-15+-2=-13







Sorry, I can't leave a video, my internet won't let me :(

Sandra's Volume Post

11. Copy and complete the chart:
blue=answer

Length Width Height Volume

a)7cm 2cm 5cm 70cm3

l

b)12cm 9cm 10cm 1080cm3

c)16cm 15cm 5cm 1200cm3

You can easily fill in this chart by simply asking yourself what multiplied by what equals the volume or creating an algebraic equation for each one. For example: a) 7x2=14, so 14xa=70m3, you replace the variable (a) with the number that best suits that equation which is 5. So thats how I figured out question 11.

16. Cindy’s aquarium stands 75 cm tall and
has a base that measures 1.2 m × 80 cm.
At one point during the initial fi lling, the
aquarium has a 12-cm depth of water in
it. Cindy needs to fi ll it to 15 cm from the
top before she adds the fi sh. Draw a
diagram and label the dimensions of the
aquarium. Determine how much more
water Cindy must add before she puts in
the fi sh.

Red=Math information

Scince you need a 15cm gap from the top you need to subtract 12 from 75 which is 63 and then you subtract 15 from 63 and you get 48. Now we have to find the volume of water we need to use in the tank.

V=lxwxh

v=120cmx80cmxh

v=9600cm2x48cm

v=460 800 cm3.

So Cindy needs to add 460 800cm3 of water before she adds the fish.

17.
A contractor is excavating a rectangular
hole 10 m × 12 m × 3 m to pour the
foundation for a house. A dump truck
with a capacity of 9 m3 is used to haul
away the excavated soil. How many trips
does the truck need to make?

Find volume of rectangular hole:

V=lxwxh

v=10mx12mxh

v=120m2x3m

v=360m3

360m3/9m3=40m3

So the truck driver will have to make 40 trips.

Cylinder Volume and Volume Problems

Cylinder Problem

Jumbo

d=r/2

d=20cm/2

d=10cm

v=πr^2 h





v=(3.14 10cm^2) 40cm





v=314cm^2 40cm





v=12560cm^3









Popcorn Lovers









r=d/2




r=30cm/2




r=15cm
v=πr^2 h




v=(3.14 15cm ^2) 20cm




v=706.5cm^2 20cm




v=14130cm^2









If Martha wants more popcorn for her money, she should get the popcorn lovers because it has a greater volume, that being said, you can fit more popcorn into it.







Volume Problem
A concrete culvert that is 10 cm long has an inside diameter of 0.8m and an outside diameter of 1m. Determine the volume of concrete required to make the culvert to the nearest tenth of a cubic centimetre.










Outside Diameter
r=d/2
r=1/2
r=0.5m
v=πr^2 h
v=(3.14 0.5^2) 10m

v=0.785cm^2 10m

v=7.85m^3



Inside Diameter

r= d/2
r=0.8/2
r=0.4m

V=πr^2 h


V=(3.14 0.4^2)h


V=0.5024m^3



To find the volume subtract the inside diameter from the outside diameter.



7.85m^3-o.5024m^3=7.3476m^3

Now we have to convert meters into centimetres.

We can do that by multiplying 7.3476 by 100, and that equals 734.76cm^3.



So you need 734.76cm^3 of concrete to make the culvert.

Surface area of a Cylinder

Cylinders
The base of a cylinder are circles, so first we have to review some basic termanology of circles:
-Radius
-Diameter
-Circumfrence
-Pi

Radius
-Half of diameter

Diameter
-Cuts circle in half

Circumfrence
-Perimeter of circle

Pi
-Ratio between circumfrence/diameter
-3.14

Now we have to review the different formulas for circles:
Cicumfrenc=∏.d=c
radius= d/2=r
diameter= 2.r or c/∏=d
Area of a circle= ∏.r.r

Net of a Cylinder:

This is a net of a cylinder:

-The height is always given to you

-the base is the circumfrence the circles

-To calculate the surface area you have to add up the lateral area (LxW) and other formulas such as...

LxW

∏.r.r=A
d=2r
R=d/2
C=∏.d

For now, We are going to practice how to calculate the area, circumfrence, diameter, and radius of a circle. For these five circles, I had to calculate the area and circumfrence using the given radius or diameter. I had to plug in the given information into the formulas to find the area and circumfrence. This is how I did it.

For circle A and B, we have the given circumfrence but we have to find the radius, diameter and area. So what I did first was I found the diameter because once you have found the diameter or radius, you can find anything. I found the diameter by dividing the circumfrence by pi (3.14) and that gave me the diameter, then I could find the radius and area.

Here's a video on Surface area of Cylinders:

I hope you understand more about circles and cylinders, please notify my if I made any mistakes or if you have any suggestions for my post. Thanks!

Sandra's Percent Video

Percent
In this unit we learned about percents. Percent means out of 100 s0 percents are always out of 100. We learned how to represent percents using 100 grids, you can convert percents into decimals or fractions, you can find a percent of a number, and you can combine percents to find things like the total cost of an item including tax.

4.1 Representing Percents

In this unit we learned how to represent percents using hundred grids. For example, if you have 30% you can represent this by shading in thirty squares in the hundred grid. Or if you have 250% your can represent this by shading in 2 hundred grids and fifty squares in another hundred grid. If you want to represent 0.25% or 1/4% you shade in part of one square and then have an arrow pointing to a square representing 1/4.



4.2 Fractions, Decimals, and Percents

We also learned how to represent percents by using decimals or fractions. We learned how to convert fractions into decimals and percents(EX: 1/4=0.25 or 25%) we learned how to convert decimals into percents and fractions (EX: 0.25x100=25% 1/4) and also converting percents into decimals and fractions.

4.3 Percent of a number

We learned how to find a percent of a number using mainly ratio tables. Another way to find a percent of a number is by turning the percent into a decimal by dividing it by 100 and then multiplying it by the number. For example: 65% of 250 0.65x250=162.5.


4.4 Combining Percents

We can combine percents when solving problems, such as finding the added tax to the cost of an item. It can be also used for finding discounts on prices. For example: GST + PST=12% tax, original price is $40 so $40x1.12=$44.80.

This is my Video on Percents:

Here's a Link about percents: http://www.mathgoodies.com/lessons/toc_vol4.html

I hope you enjoyed my video!

Percents

Percent Problem:

Over five years, the circulation of a magazine increased from 25000 copies to 150000 copies. What percent is the new circulation of the circulation from five years ago? What is this percent as a decimal and a fraction?

For this problem, we would want to use the math information given to us:

-5 years of circulation

-25000 copies

-150000 copies

Fraction out of 1oo.

OF means the denominator of the fraction.

Now, to solve this problem, we are going to use proportion.

Fraction: 600/1oo or 1/6

Percent: 600%

Decimal: 600%/100=6

Here's a video to help you:

Here's a website I found on percents:

http://www.mathgoodies.com/lessons/vol4/meaning_percent.html

*Remember* Do pages 40-41 in the homework book, also for our class, we have a Social Studies Test tomorrow, so don't forget to study! I hope everyone does well:)

Pythagoras

Right Triangle

A right triangle needs to have a right 90 degree angle and have three sides.
The sides that make up the right angle are called the legs.


Side C is the hypotenuse.
The hypotenuse is always located opposite of the right angle.
The hypotenuse will always be the longest side on a right triangle.



This is a video that talks about the sides of a right triangle, it's pretty much the same thing, but its just to gain a visual perspective on the right triangle. If any of you found a link to a video or website, you can put it in your comments, that would be very much appreciated.






Here's todays homework:

You have to explain this equation: a2+b2=c2 (A squared plus B squared equals C squared, sorry I can't seem to make a proper exponent symbol for this). You can try to figure it out on your own, or you can do some research on it, the equation is made from an ancient Greek person called Pythagoras.



*Remember to study for the math test tomorow!*

I hope you all do well!

Sandra's Sesame Street Video

Members:


Duyen: The store clerk


Leea: The camera person


Sandra (me): the customer trying to find the best value for the bears





Ratio


Two term ratio: Compares two quantaties measured in the same units.


Three term ratio: Compares three quantaties measured in the same units.


Part to part ratio: Compares one part of a group to eachother.


Part to whole ratio: Compares one part of a group to a whole group.


Example of a ratio used in our video would be: 1 teddy bear:the total of stuffed animals, which would be a part to whole ratio.





Rate


Rate: Compares two quantaties measured in different units.


Unit rate: a rate in which the second term is one.


Unit price: a unit rate used when shopping.


Example of a rate used in our video would be: $1.50/stuffed animal, $4.00/stuffed animal which would be a unit price.





Proportional Reasoning


Proportion: a relationship that says that two ratios or two rates are equal.


Example of a proportion used in our video would be: figuring out which stuffed animal would be a better value using two rates.




Part one:
The original video is Banana sign, we changed our video allot so it is not exactly like the original, we didn't even use sign language in it, so we used the sesame street video as our inspiration. What happens in the video is that Samara is trying to tell Telly she wants a Banana in sign language, but Telly doesn't understand her until the end of the video.
http://www.sesamestreet.org/video_player/-/pgpv0/37899ce0-7d5a-42bc-a93a-3a31369b42/banana_sign






Part two:
This is our Video that we made, we have two because the camera caught us off on the first video.

Sandra's Math Profile

If Someone asked me "Do you like math?" I would probably answer "yes, but I am not very good at it". I would love to be good at math, it is so interesting, complex, and you need math in the real world. I definately want to improve on my math skills and to understand math better. The best thing I ever did in math class was in grade's five and six when I was actually starting to understand math better than I ever did before. We learned different strageties so we could actually understand the problem, and my math teacher explained it in a fun and interesting way.

Last year in grade 7, my best unit would have to be probably about factors. I was also good at percentages and area of parallelogram, triangle, circle etc. Why I did well on factors was that it was the only math test where I got a perfect 100% test score, I remember feeling happy for the rest of the day after that. I was good at percentatges because I understood how to convert then and to relate them to fractions and decimals. And the area and measurement because I loved how the math information and numbers fit in so well into the formulas. The units that made me struggle however, were dividing decimals, big "unfriendly" decimal numbers are so hard to work with and I had a difficult time understanding them. I also had a hard time adding or subtracting improper fractions, that I had trouble with, I tried the method of cross multiplying, but the whole strategy was to complicated for me to grasp. But I have to say the unit that was worst for me was probability. I knew about percentages of things and all that, but I had problems with organizing the events in tables and charts, all of that just annoyed me for some reason. What I am planning to do this year to try not to struggle so much in those areas is to seek out more help because I am at school to learn and to improve. Another thing I could do is to study harder, so if I read it for a few times over I might actually get it, or inquire more on the subject and research it.

What I want to do this year to become more succesful in math is to ask more questions, get help if I need it, do more research, and try to learn better by focusing and studying smarter. Another thing is to work on my speed. I tend to take my time too much, so I really need to work on my speed, it will really help with my tests and my final exam. I really want to do much better in math this year, so I will have to put in allot of effort. What I would like to learn this year is maybe trying to link math with science. Science is my favourite subject, and I know math has allot to do with science, in fact, math is science, mathematics is the science of numbers and patterns. Anyway, I would just like to learn more about math period.

The blog post I did last year was on mixed numbers and that was the only post I ever did, the reason for that is because while I was making my post I didn't really knew exactly what I was doing so next to sign in, I clicked create blog instead, little did I know I was supposed to sign in and click on new post, when I realized that I couldn't find what I posted, I created several different replicas of my post and posted them again, and I still could only see them on my personal account. Finally, I talked to Mr. Isfeld and he showed me the correct way of doing it. After that he never picked me again to do the blog, and I think I know why, but I can post properly now. Anyway, back to talking about math, I really enjoyed making that blog post, it was a good learning experience for me and it was fun too, I was quite proud of my post, I added pictures and a couple of video links and I put effort into it. I really enjoyed getting feedback from my peers through their comments. You can see my blog at this link:http://wwwspkgrade7math09-sandra43.blogspot.com/. What I would like to do on the computers in math this year is to create more blog posts, and maybe making pictures and videos and adding them to my blog.

Well, this was my math profile, I hope you enjoyed it, and I hope everyone has a great year in math!