Multiplying and Dividing Fraction

Multiplying fractions is very easy. First, you reduce your fractions. For example, 2/3*1/2. You can divide the twos by two because the greatest common factor of both numbers is two. This is because one is a numerator and one is a denominator. So the fractions become 1/3*1/1. Then, you multiply the numerators and the denominators. In this case you get (1*1)/(3*1) so the answer is one third or 1/3.
To divide you do the same thing as multiplying but you multiply the first fraction by the reciprocal of the second fraction. For example, 4/5 divided by 3/6 equals 4/5*6/3. You can reduce before and after you find the reciprocal of the second fraction. The answer is 24/15 which can be reduced to 8/5 and that equals 1 and 3/5. Remember, when dividing always find the reciprocal of the second number and never the first.

Posted by Duncan D.

ADDING and SUBTRACTING FRACTIONS

Today in math class, after we went over our homework we learned how to add and subtract fractions. Adding and subtracting fractions is like adding and subtracting numbers except there is a numerator and a denominator. Both the numerator and the denominator are added and subtracted by each other so like the line thing that separates them is like a line separating two different kinds of problems. This is easy until there are letters that I forget what they are called come into play. When you add or subtract a fraction with a letter/symbol thing, you have to times the numerator by what ever the denominator was multiplied by. So three over five and W over 15. Because the two denominaters are 5 and 15, you divide and you get 3 so you do 3 times 3 and get for the other denominator 3W. This is adding and subtracting fractions

-Dan

Adding & Subtracting Fractions

Here's the work we did today with adding and subtracting fractions with negative numbers and variables.

5.3 Rectangles

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Converting Fractions to Decimals

Today in class we learned about converting fractions to decimals. You do this by dividing the numerator by the denominator.For example 4/5 is equal to .80. This is because 4 divided by 5 is 0.8 so that is the decimal. Sometthing a little more complicated is say -4 and 7 tenths is -4.7 because 4 is the whole number so thats where you get the 4 and 7 tenths is just the same as 0.7.

We also learned about about how to convert decimals to fractions; in their simplest form. All you have to do is 0.25=25/100=25/100 divided by 25 = 1/4. when doing this you always want to right the fraction in simplest form.

Also you can do 0.625=625/1000=625/1000 divided by 25 is 25/40 which divided by 5 is 5/8.

Least Common Multiple and Fractions

Here are our notes from today.

Ch. 5 2 Rectangles

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Least Common Multiples

Today we learned about least common multiples. The least common multiple of two numbers is the smallest number (not including 0 or 1) that is a multiple of both. It basically means that if there are two numbers, the least common multiple is the multiple that both numbers have in common. Example- What is the LCM(least common multiple) of 3 and 8?

Multiples of 3- 3, 6, 9, 12, 15, 18, 21, 24...

Multiples of 8- 8, 16, 24, 32...

LCM of 3 and 8- 24

Multiples do NOT mean factors. A non example would be to say that the least common multiple of 6 and 8 is 2. Don't get multiples mixed up with factors. Another way to find multiples is to do a venn diagram. Example- What is the LCM 16 and 36? It is not possible to do one on here, so I'll try my best. Put 16 and 34 in a venn diagram. 16 in one circle, and 34 in the other. Put what they have in common in the middle.

16 - 2*2*2*2 They have 2 in common. 34 - 2*17

Cross one 2 from each one.

That leaves 2*2*2*17-----2 cubed *17

8*17

LCM- 136

-Katy DiMuzio :)

Least Common Multiple

Our notes from today on finding least common multiple with prime factorization.

Ch. 5.1 - Least Common Multiple

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GCF of variable expressions, simplifyng algebraic fractions.

Today in class we learned about finding the GCF of variable expressions, and how to simplify algebraic fractions. Even though it looks hard finding the GCF of a variable expression its pretty easy. First you have to find the prime factorization of the number. Like if the number in the expression was 6 the prime factorization would be 2*3. After that you would write the variables out in expanded form. So if the whole expression is 6ab then when you write it out you would have 2*3*a*b. Then you find the common factors.

Example:#1
Find the GCF of 6ab and 8xy
6ab = 2*3*a*b 8xy = 2*2*2*x*y
They both have 2 in common so the GCF would be 2.

Then we reviewed equivalent fractions and also how to simplify fractions. Also we learned how to simplify algebraic fractions. First you have to write the prime factorization of the expression. Then divide the numerator and denominator by the common factors.

Example:#1
4xy^3/ 8ax^2=2*2*x*y*y*y/2*2*2*a*x*x= y^3/2ax

Example:#2
2mn/4m= 2*m*n/2*2*m=n/2

GCF of variable expressions, simplifying algebraic fractions

4.3b & 4 Rr

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hello class im excited to begin this learning journey with the rest of my classmates. This should be a differant new thing and a wonderfull thing at that, lets go red rectangles.

Primes, Composites, Prime Factorization

Yesterday in class we learned about prime numbers, composite numbers and the GCF of a number. A prime number is a positive integer that is not divisible without remainder by any integer except itself and 1, for example 7 is a prime number because its only factors are 1 and itself. A composite number is a number that is a multiple of at least two numbers other than itself and 1, an example of a composite number is 20 because its factors are 4, 5, 1, 20, 2 and 10 but 7 would not be a composite number, neither would 3, 5, 13, 23 and many more. The GCF or greatest common factor of a number is the largest number that is a common divisor of a given set of numbers. An example of this that the GCF of 10 and 20 is 10 because 10 is a factor of both numbers and its the biggest factor for both numbers. Yesterday we also learned how to find the prime factorization of a number by doing the upside division rule. We also learned that you can find the GCF of 2 numbers by using a venn diagram.

by Quillen B

Primes, Composites, Prime Factorization

Class notes on prime and composite numbers; how to use prime factorization to find the greatest common factor.

Primes & Composites, GCF

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Today in math, we learned about exponents. Exponents can be used to show repeated multiplication. For example: 2 to the 5th power=2*2*2*2*2=32 NOT 2 to the 5th power is equal to 10. We learned that a power has two parts: the base and an exponent. The base is the main number, and the exponent is the raised number.
Examples:
4*4*4*4= 4 to the fourth power
3*x*y*y=3xy to the second power
We also went over the divisibility rules for numbers 1,2,3,4,5,9, and 10.
Examples:
1: every number is divisible by 1
2: ends in 0,2,4,6,8,10
3: sum of digits are divisible by 3
486~~~4+8+6=18 is divisible by 3
4: last 2 digits are divisible by 4
594~~~9+4=13 is not divisible by 4
5: ends in 5 or 0
9: sum of digits are divisible by 9
548~~~5+4+8=17 is not divisible by 9
10: ends in 0

Divisibility Rules, Factors, Exponents

Lesson on Chapter 4.1 & 4.2

Chapter 4.1 and 4.2

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