A variable is a letter that represents an unknown number.

An example would be any letter like x, a, v, y, o, etc.

An expression is any single number or varible, or combination of operations involing numbers and variables. Some examples would be 3, x. 4y, +, -, ÷

## Friday, February 17, 2012

## Tuesday, February 14, 2012

### definitions

new defintions

constant number- a number that does not change and it increase or decrease the

value of an expression.

constant number- a number that does not change and it increase or decrease the

value of an expression.

### definitions

new definitions

expression- any single number or variable, or combination of operations

involving numbers and variables

5,n,8+,x+1,2y-7,etc

expression- any single number or variable, or combination of operations

involving numbers and variables

5,n,8+,x+1,2y-7,etc

## Monday, February 13, 2012

### Homework Booklet Chapter 7.4 Question 7.

Homework Booklet Chapter 7.4 question 10.

Lars ran 6 2/3 laps of the track at his school. Reneta ran 8 1/4 laps.

A) How much faster did Reneta run? Show your work.

First I turned 1/4 and 2/3 into a common denominator, which is 12.

1/4 X 3 = 3/12.

2/3 X 4 = 8/12

So after that I subtract 8/12 from 3/12 but you can't do that 'cause you'd get -8/12 or something. So you take a whole number, change 8 to 7 and now it's 15/12 - 8/12 which is 7/12.

Then 7-6 = 1.

1 + 7/12 = 1 7/12

B) Check your answer using estimation.

6 2/3 rounded off to7.

8 1/4 rounded off to 8

8 - 7 =1.

Lars ran 6 2/3 laps of the track at his school. Reneta ran 8 1/4 laps.

A) How much faster did Reneta run? Show your work.

First I turned 1/4 and 2/3 into a common denominator, which is 12.

1/4 X 3 = 3/12.

2/3 X 4 = 8/12

So after that I subtract 8/12 from 3/12 but you can't do that 'cause you'd get -8/12 or something. So you take a whole number, change 8 to 7 and now it's 15/12 - 8/12 which is 7/12.

Then 7-6 = 1.

1 + 7/12 = 1 7/12

B) Check your answer using estimation.

6 2/3 rounded off to7.

8 1/4 rounded off to 8

8 - 7 =1.

### Isfeld's Math problem. Explained by me, Aniane Canuto.

Okay, I've been seeing people re-posting Isfeld's expression word problem with the answer, but there's no explanation why.

This post will explain the following:

1. What the problem is

2. How to get to the answer

3. The answer

4. Why that answer?

Ok, Explanation number 1:

*A group of students are talking, 2 students leave the group. Write an expression for the number of the students in the group after the 2 leave.*

Explanation number 2:

We learned about variables, so a variable must be involved here.

We know that 2 students leave the room. And that would be a synonym to subtraction, so that

should be involved here as well.

We have absolutely no idea how many people are in the group, so we need something to mark in the expression that proves the group is an important part of this.

Hmm...what was that word again?

*Variable: A letter that represents an unknown number.*

Explanation number 3:

G-2

Explanation number 4:

*(Note: This is basically a retell of number 2, so you can leave at this point)*

Why G?

It's a variable. We don't know how many people are in the group, so we use the letter G to represent the group altogether.

What's with the minus sign?

Students leaving the group is like a number taking away another number. And a number taking away a number is subtraction, and subtraction has the word "minus" involved.

Why is 2 there?

Because that is the number of students that we are sure of that left.

And there we have it, Isfeld's question explained entirely by me.

### Let's go over our notes: Expressions & Variables

Variable: A letter that represents an unknown number.

Example: x, a, n, y, etc.

Expression: Any single number or variable, or combination of operations involving numbers and variables.

Example: 5, n, 8, 8t, x + 1, 2y - 7

*Note: There are no equal signs (=) in an expression.*

Value: A known or calculated amount.

Numerical Coefficient: A number that multiplies the variable.

Example: 2t

("2" is the numerical coefficient, "t" is the variable.)

### Finding a percentage of a number.

Old topic, I know.

But I know of an easy way to find a percentage of any number, and I want to share this on the blog.

Let's pick a number, shall we?

How about.....53

Let's find 64% of 53

So to find the percentage, find 1% of the number.

(which is done by dividing your number by 100)

1% of 53 is 0.53

Then multiply that number by the percentage you're trying to find.

I got 33.92

So there we have it, 64% of 53 is 33.92.

### Number of the day instructions (As of February 13, 2011)

Number of the day Instructions (as of Feb. 13, 2012)

I'll use 1234.567 for some of my examples for this overview.

n = number (In case if you are a dimwit.)

1.

*Half of the number is*......(Basically n ÷ 2)
2.

*Write the number in expanded form.*(You represent the value of each digit. It should look something like this: 1000 + 200 + 30 + 4 + 0.5 + 0.06 +0.007)
3.

*Write the number in written form*. (Just write it as it is said)
4.

*Round to the nearest 100*. (Look at the hundreds place, if the tens digit is 5 or higher, add one to the hundreds digit, if the number is lower than 5, the digit stays the same and all the digits to the right gets replaced by the number 0.)
5.

*What digit is in the ten*. (Take note of the "ths," Basically the first number from the decimal point left to right.)**ths**place
6.

*The number of the day doubled is*.....(Basically n x 2)
8.

*Write a power using the 100ths place as the base, and the digit in the 10s place as the exponent.*(A power is basically this:^{ }^{ }^{ }
The big number is called the base, and the small number is the exponent.)

9.

*Write the above number in factored form.*(Factored form, just a note of this:)
It's NOT this:

1 x 2 = 2

It is however this:

1 x 1 = 1

Moving on.

10.

*Cube the number in the ones place.*(A cube is a number with 3 as it's exponent. So it would be: n x n x n = n.)

11.

*Square the digit in the hundreds place*. (A square is a number with 2 as it's exponent, so:
n x n = n)

12.

*Divide the number by 3.55 and round to the nearest hundredth.*(n x 3.55 = something like 347.77. Refer to #4 for how to round.)
13.

*The product of the digits is*... (Just multiply all the digits)
14.

*List all the prime numbers in the number of the day.*(A prime number is a number with 2 factors: 1 and itself. Basically the prime numbers for any number of the day are contain at least one of the following: 2, 3, 5 & 7.)
16.

*The whole number is divisible by*....(Refer to my post "Divisibility Rules Overview," for divisibility rules.)
17.

*Using the digits in the 1's and the 10's place respectively make a number and list the prime factors.*(Refer to #14 for info on a prime number.)
20.

*Write a fraction using the 1000s place as the denominator and the tenths place as the numerator.*(Refer to my post "Number of the Day Question #20" for this. I don't want to explain myself twice.)
21.

*Use any of the digits to make a proper fraction.*(A proper fraction is basically when the numerator is smaller than the denominator.)

22.

*Use any of the digits to make a mixed number.*(A mixed number is composed of a whole number, and a*proper fraction.*)

*23. Write the answer to number 21 as a decimal.*(Just divide the numerator by the denominator.)

*24. Draw a picture to represent the answer to number 21.*(How to do this is straightforward.)

*25. Write the answer to number 21 as a percent.*(Just take the answer to #23 and multiply it by 100.)

^{}

### number of the day- 1234.567

5.) what digit is in the tenths place: 5

### number of the day- 1234.567

4.) round to the nearest 100: 1200

### number of the day- 1234.567

3.) one thousand, two hundred, thirty-four and five hundred sixty-seven thousandths

### number of the day- 1234.567

2.) write the number of the day in expanded form:

1000+200+30+4+0.5+0.06+0.007

### number of the day- 1234.567

1.) half of the number of the day is: 617.2835

### Question

A group of students are talking 2 friends leave the group write an expression for the number of the students in the group after the 2 leave.

Answer - g-2

Answer - g-2

### Expression

Expression - Any single number or variable, or combination of operations [plus, minus, multiply, divide]

eg 5, n, 8+, x+1, 2y-7

eg 5, n, 8+, x+1, 2y-7

### Number of the day

Number : 4352.697

1. Half of the number : 2176.3485

2.expanded form: 4000+300+50+2+0.6+0.09+0.007

3.four thousand three hundred fifty two and six hundred ninety seven thousandths

4. round to the nearest 100: 4400

5. the digit in the tenths place: 6

1. Half of the number : 2176.3485

2.expanded form: 4000+300+50+2+0.6+0.09+0.007

3.four thousand three hundred fifty two and six hundred ninety seven thousandths

4. round to the nearest 100: 4400

5. the digit in the tenths place: 6

### Divisiblity Rule for 5

Divisibility Rule for 5 - the last digit of a whole number has to be either 0 or 5. (The quotient has to be a whole number).

eg. 5, 10, 15, 20, 25, 30, etc.

eg. 5, 10, 15, 20, 25, 30, etc.

### Meanings

variable - a letter that represents an unknown number

eg. x, a, n

expression - any single number or variable or combination. Involving numbers and variables.

eg. 5, n, 8t, x=1, 2y - 7

value - a known or calculated amount.

eg. x, a, n

expression - any single number or variable or combination. Involving numbers and variables.

eg. 5, n, 8t, x=1, 2y - 7

value - a known or calculated amount.

### Definitions

An improper fraction - is a fraction that has a greater numerator than the denominator.

eg. 9/8, 5/2, 7/3

eg. 9/8, 5/2, 7/3

### three yearsago samshight was 108cm since that time has grown 25% in hight

A) How much has he grown- 27cm

B) how tall is he now- 135cm

B) how tall is he now- 135cm

## Sunday, February 12, 2012

### Subtracting Fractions with like denominators #4-5

4.a)6/6-2/6=4/6=2/3

b)2/3-1/3=1/3

c)4/6-1/6=3/6=1/2

5.a)2/3-1/3=1/3

b)3/6-1/6=2/6=1/3

c)4/4-1/4=3/4

b)2/3-1/3=1/3

c)4/6-1/6=3/6=1/2

5.a)2/3-1/3=1/3

b)3/6-1/6=2/6=1/3

c)4/4-1/4=3/4

### #2 Order of Operations

(102+1)-15\3x3

do the ones n the brackets first so 10x10=100+1=101

next do 15\3=5 then times it by 3=15

last but not least do 101-15=

**86**### Number of the Day #1,2,3,4,5,6,8,9,10,11,12

Today's Number is: 2319.456

1. Half of the number of the day is: 159.728

2. Write the number of the day in expanded form: 2000+300+1+9+0.4+00.5+000.6

3. Write the number of the day in written form: Two thousand three hundred nine teen and four hundred fifty six thousandths.

4. Round to the nearest 100: 3

5. What digit is in the tenths place: 4

6. The number of the day is: 4638.912

8. Write a power using the digit in the 100th place as the base and the digit in the 10's place as the exponent: 59

9. Write the above factored form: 5x5x5x5x5x5x5x5x5

10. Cube he digit in the ones place: 9x9x9=729

11. Square the digit in the ones place: 3x3=9

12. Divide the number of the day by 3.55 and round to the nearest hundredth: 6533.678

### Ordering decimals from greatest to least

Q. 2.0287; 0.287; 1.8954; 1.0287

First you look at the whole numbers , If they all have whole numbers see which has has the greatest and if they don't, move on to the tenths.

In the tenths you do the same thing you look for which has the greatest

For the hundredths and thousandths you also do the same thing.

A. 2.0287, 1.8954, 1.0287, 0.287

### numerical coefficient definition

numerical coefficient- a number that multiplies the variable

examples 2t

examples 2t

### #6,8,9,10,11 Number of the Day

Today's number is 3648.972

6.7297.944

8.74

9.7x7x7x7

10.512

11.36

### Adding Mixed Number

A mixed number is a number made up of a whole number and a proper fraction such as...

1 2/3 correct 2 3/2 wrong

eg. 1 1/2 + 1 1/4 =2 3/4

An Improper fraction - is a fraction that has a greater numerator than the denominator

eg. 9/8, 5/2, 117/3

### #1-5 Number of the day

Today's number is 3648.972

1.1824.486

2.3000+600+40+8+0.9+o.07+0.002

3. Three thousand six hundred forty eight and nine hundred seventy two thosandths

4.3600

5.9

### Bedmas Question

18-(3x4)+2-(5 2 )

18-(3x4)+2-25

18-12+2-25

18-14-25

18-11=

7

### Definition of expression

expression: any single number or variable, or combination of operations involving numbers and variables.

example: x+2

### Bedmas Question

7x3 2 - ( 4x4 2 ) ( Numbers with a space from each other are exponents )

7x3 2 - ( 4x8 )

7x3 2 - 32

7x6 - 32

42 - 32 =

10

7x3 2 - ( 4x8 )

7x3 2 - 32

7x6 - 32

42 - 32 =

10

### How to add fractions with the same denominator

When you add fractions with common denominators, you have to add is the numerator and when you get the sum of adding the 2 numerators you put the sum as the numerator and the denominator you had as a common denominator the denominator.

### Constant Definition

Constant- A number that does not change the value of an expression.

### Divisibility Rules

Rule for

1, all whole numbers are divisible by 1

2, all even whole numbers are divisible by 2

3, add up the digits and if the sum is divisible by 3 the number is divisible by 3

eg.4545, 4+5+4+5= 18 18 is divisible by 3 meaning 4545 is divisible by 3

4, If the number is divisible by 2 twice with no remainder

5, all whole numbers that end in 0 or 5 is divisible by 5
### Divisibility Rule for 2

All of the even numbers are divisible by

**2**like numbers that end in

**0,2,4,6,8**### isfeld's question

Q.a group of friends are talking 2 friends leave . come up with an expressionfor the number of students in the group after 2 leave.

A.G-2

A.G-2

### constant definition

constant- a number that does not change the value of an expression.

example 23+2-0x1

example 23+2-0x1

### expression definition

expression- any single number or variable combination of operations involving numbers and variables.

example a+3-2

example a+3-2

### Definition - Numeral coefficient

Numeral coefficient - A number that multiplies the variable.

Example - 2 is the numeral coefficient , and "W" is the variable.

Example - 2 is the numeral coefficient , and "W" is the variable.

### Definition - Constant

Constant - A number that does not change and it increases or decreases the value of an expression.

### Definition - Variable

Variable - A letter that represents an unknown number .

Example. X , A , N , B , T , G

Example. X , A , N , B , T , G

### Definition- Expression

Expression - Any single number or variable , or combination of operations involving number and variable ( - , + , x , ÷ )

Example. 5 , N, 8T , X + 1 , 2y - 7

5 x w

15 x p

Example. 5 , N, 8T , X + 1 , 2y - 7

5 x w

15 x p

### Number of the Day Question 23

The answer for question number 23 is 0.5 because if you convert three sixths in half it will be 0.5.

### Number of the Day Question 23

The answer for question number 23 is 0.5 because if you convert three sixths in half it will be 0.5.

### How to add fractions with the same denominator

When you add fractions with common denominators, all you have to add is the numerator and when you get the sum of adding the 2 numerators you put the sum as the numerator and the denominator you had as a common denominator the denominator.

Here is an example of adding fractions with common denominators.

Here is an example of adding fractions with common denominators.

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