# Math Reflection-_- (muhahaha!!:P)

In this math class, which is 7B math class, we had Mr.Fedley as our teacher. This semester we studied ratio, algebra, angles and statistics.

I did a lot of activities this semester. For the ratio unit, we did a blog post on using ratio to estimate sizes. Me and my friend Ashley use the computer to estimate the size of a door. We also did a another activity on explaining different types of ratio. My partner was also Ashley. We did a ratio for the number of the stairs in one of the buildings in YIS to the number of stairs in another building in YIS. In addition, we went to the YIS cafeteria and did a ration on the number of chairs in the left side to the number of the chairs in the middle of the number of the chairs on the right side.

For the algebra unit, we didn’t actually do any activities because we were mostly focusing on the textbook work.

For the angle unit, we did an activity on making our own angle questions and then let other students to answer.

For the statistics unit, everyone have to find 20 data in the real world or on the internet. Then, we have to find the mean, mode, median and range. I found the data of  the teams reaching top four in FIFA World Cup. It was actually pretty hard because it has a  lot of numbers so it’s very easy to get a mistake.

The data

I found ratio the most challenging because the age problems that uses ratio is very hard to understand and work out. However, as I practice more and more by myself at home, I got better at it.

Next year, I want to focus more on ratio from this semester’s unit. Although, I got better at  the age problems, I still want to focus more on it because it’s very hard to understand and ratio things are very easy to forget for me. I am scared that I will forget all of it during the summer break, so I wish that I could focus on ratio again next year.

# Starting Statistics

In math class, we started our new unit, which is statistics. Statistics is the branch of mathematics that is concerned with the gathering and organisation of numeral information called data. There are three basics steps:

• Collecting the data
• Sorting the data
• Analysing the data

Everyone have to find 20 data in the real world or on the internet. Then, we have to find the mean, mode, median and range.

On the internet, I found the data of  the teams reaching top four in FIFA World Cup. This is the data:

Range- Range is the difference between the lowest and highest values. The range of the data is 11 because 12(the biggest number in the data) subtract 1(the smaller number in the data) is 11.

Mean- Mean is the average of the numbers: a calculated “central” value of a set of numbers. The calculation is adding the whole numbers and then divide by how many numbers there are. The mean of the data is 3.6 because (all the numbers in the data) 10+8+12+4+5+5+2+2+4+The+2+4+2+2+2+1+1+1+1+2= 72 and then 72 divide 20(how many numbers there are) equals to 3.6.

Median- The middle number in a list of numbers. To calculate, you have to put the numbers from smallest to biggest, and then find the middle number.  The median of the data is 2 because if you put it order:

1 1 1 1 2 2 2 2 2 2 2 2 4 4 4 5 5 8 10 12

there is two middle numbers, so then you have to add them(2+2) and then divide the added number with two, which is 4 divide by 2 equals to 2.

Mode-  The number which appears most often in a set of numbers.  The mode of the data is 2 because if you put the numbers in order, you will see that 2 appears the most.

1 1 1 1 2 2 2 2 2 2 2 2 4 4 4 5 5 8 10 12

(All the definitions of the words are from http://www.mathsisfun.com/)

My data tells me that a lot of team reaching top four got it two times. Also, the average of the team reaching top four is about 3-4 times.

# Grade 7 Math Exam Topics: Ratios and Algebra

In YIS, next week, April 28-May 1 is going to be a big exam week. For math, the exam is going to be about ratios and Algebra.

The two ideas I know about Ratios is:

• Always multiply, divide the numbers by the same value. {E.g. 3:2 (all times by 2) = 6:4}
• Ratio compares different values, it’s used in a lot things instead of another symbol that you won’t very notice. {E.g. The rate, 6liters/hour, in ratio is 6liters:1 hour}

The two ideas I know about Algebra is:

• Mostly everything you find in math, all has something to do with algebra. {E.g. Solving the angles of a shape.}
• If there is an equal sign in a problem, it means it’s a equation. If there is no equal sign in a problem, it means that you have to finding like terms. {Eg. 4x-1+5x+2——->this is a equation     5x+4y+7+8+9+6u+5y————->this is finding like terms}

QUESTIONS on ALGEBRA and RATIO!!

1. 9:3 —–> ?:21
2. What’s 7kg/hour in ratio?
3. What’s the angle of the following?
4. Find the “x” angle in the following shape.

Which topic did you find more interesting?

I found algebra more interesting because algebra is very useful that it’s used in a lot of math topics like finding the angle of a shape, finding the area of  a shape etc. Also, algebra has a lot of different kinds of expression so it was interesting.

Which topic or concept did you find most challenging?

I found ratio more challenging because sometimes its hard for me to understand the ratio word problems and when other people show me how to do it, I can’t even understand it. If I use algebra to solve ratio word problems, it will be much more easier for me.

What can you do to improve your knowledge of your two topics?

I can review sometimes(rote repetition) so I can always remember the concept and I can always remember how to do ratio and algebra questions.

# Explaining Ratios

Ratio is something that compares to another thing.

Example:

Ratio of Four to Three

Ratio can be shown in a lot of different ways like:

• Using the “:” to separate the values ~ 4:3
• Instead of using “:” you can also use the word “to” ~ 4 to 3
• Or write it as a fraction ~ 4/3

The trick with using ratio is to always multiply or divide the number by the same value, for example:

4:5 is the same as 4 x 3 : 5 x 3 which equals to 12:15.

Me and Ashley work together as a group and 2 distinct, interesting ratios:

The Pauli Building stairs!!

THE FIRST RATIO!!

We were investigating the ratio of the stairs at the Pauli Building of the stairs at the Drama Building. There were 24 stairs at the Pauli Building and 44 stairs at the Drama Building. Therefore, the Ratio is 24:44! However, you can simplify it because 24 and 44 is all a multiple of 4, so it equals to 6:11.

As you can see, you can simplify ratios! Just like simplify fractions! If a ratio can be simplified by a number, must SIMPLIFY, if you don’t, in test you might get a mark off! For example: 56:63 is all the multiple of seven, therefore it is 8:9.

Cafeteria

THE SECOND RATIO!!

In the YIS cafeteria, there are 35 tables in total. We counted that there were 11 tables on the right, 6 tables in the middle and 16 tables on the left. Therefore, the ratio is 11:6:16. As I said in the front, if the ratio can be simplified, then simplify it. Nevertheless, this ratio can’t be simplified because the numbers are not all in a same time table group.

You see, you can have a ratio with 3 numbers or even more too right? It’s not only two numbers. For example: Elaine has a book shelf that has 3 different language book. There are 15 Chinese books, 60 English books and 30 Japanese books. Whats the ratio of English books to Chinese books to Japanese books??

• The Solution is this:  E:C:J , so it’s 60:15:30 and if you simplify it all by 15 because the numbers are all multiples of 15, it is 4:1:2

I think the following two videos might be very helpful if you have any trouble with ratios!!

# Using Ratios to Estimate Sizes

Main Building M105 room door

In math class, we have to use ratios to estimate the length or height of different objects. I was in a group with Ashley . Ashley and me estimate how many Macbook Air can going to one M105 room door.

We used a 30 centimetre ruler to measure the length of the MacBook Air. It is 18.9 centimetre ,so we round it up which equals 19 centimetre.

One M105 door equals 10 Macbook Air, therefore the ratio is 1:10(1 door to 10 Macbook Air)

I estimate that the length of the M105 door is 190 because:

ALGEBRA METHOD

1. 1:10 = 19: X

2. 10 x 19 = 1 x X

3. x = 190