作者：Claire Fischer 7 年以前
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The link discusses mixed numbers and how to work with them.
Mixed numbers are also called "Mixed Fractions."
Example:
2 + 1/4 is a mixed number.
We can multiple 4 x 2 and then we can add 1 to get 9. Our answer would then be 9/4. This is how we simplify fractions that have a bigger numerator than a denominator.
The link discusses equivalent fractions and provides problems for students to use as a form of practice.
For example:
12/6 can be divided by 2, so 12/6 is equivalent to 6/3.
Have students try the examples that are listed at the bottom of the weblink for How to Simplify Fractions.
The attached video link gives a visual of how students multiply fractions.
Example:
3/1 x 3/8 = ____
We don't have to find a common denominator when multiplying.
We simply multiply our numerators: 3 x 3 = 9. Next, we multiple our denominators: 1 x 8= 8. Our answer is then 9/8. This is a mixed fraction which we will learn about later.
Use the attached link to discuss dividing by fractions with students.
We use reciprocals more often when we are using equations and we need to move fractions from one side of the equation to the other.
For instance if we have:
5 = 2/3x
We need to multiply 2/3 by it's inverse to "Cancel" it out. The inverse is 3/2. The inverse is then multiplied by 5, on the other side of the equation:
5/1 x 3/2= 15/2 (7+1/2).
so, X=15/2 (7+1/2)
Algorithm 3 asks that we use the inverse-and-multiply rule:
Example:
5/6 divided by 1/3=____
Our numerators are 5 and 1. Our denominators are 6 and 3. We multiply our numerator from the first fraction with our denominator from the second fraction= 5 x 3= 15. We then multiply our numerator from our second fraction and our denominator from our first fraction 1 x 6.
Our new division problem becomes:
15/6 (In a mixed fraction this is equal to a simplified 2 + 1/2)
Using this algorithm, we want to find a common denominator, just like we do when we add or subtract.
Example:
7/14 divided by 6/7= ____
multiples of 7: 7, 14, 21
multiples of 14: 14, 28
Our least common denominator then is 14.
7/14 does not have to change, but we need to change 6/7 so there is a 14 in the denominator. To do that, we multiply 7 by 2 and we have to also multiple our numerator by 2. So our new division problem is:
7/14 divided by 12/14= _____
Since we have the same denominator, we only divide our numerators, so our answer is 7/12.
Find common numerators:
3/4 divided by 1/8:
Let's use the numerator of 3.
3/4 already has a numerator of 3. So we just need to change our second fraction's numerator: 3x1= 3. What we do to our numerator, we must also do to our denominator, so we must multiply 8 by 3 as well, which equals 24.
Our division problem is now:
3/4 divided by 3/24.
Our 3's do not change, instead, we just divide our denominators=
4/24 (1/6).
*To find a common denominator we have to think of common multiples for both numbers in the denominator!
Example:
5/7-3/7= _____
Refer to above link in Adding Fractions for finding a common denominator
Example:
2/3 + 1/3= _____
You might have to find a common denominator
Example:
2/5 + 3/4 = ____
*Think of the multiples of 5 and 4
5: 5, 10, 15, 20
4: 4, 8, 12, 16, 20
The common multiple is 20, and we can use it as our denominator. How many times did we multiple 5 to get 20? 4. So 4 x 2= 8 which equals: 8/20 + 3/4. Now let's change our fraction of 3/4 so that it also has a denominator of 20.
We multiplied 4, five times, to get 20. So 4 x 3= 12. 12/20
Our new fractions are:
8/20+12/20= 20/20 = 1.
Number lines can be used with fractions to show parts of a whole. If we have a number line from 0 to 1, we can mark our number line with integers that are between 0 and 1. These integers are fractions, such as 1/4, 1/3, and 1/2. Number lines can give us a visual representation of these fractions.
Use this interactive set model link to demonstrate how fractions display parts of sets. Have students practice along with you and answer the questions that are provided in interactive lesson.
Use the fraction strips worksheet that is attached to this subtopic. This will give students a visual of what fraction strips are. Use the second worksheet that is blank, to ask students to color in the fractions that are provided.
Colored regions are used to visually show what a unit looks like when it is subdivided into multiple regions.
This is the bottom part of the fraction.
Example:
In the fraction 2/3, the denominator is the 3.
This is the top part of the fraction.
Example:
In the fraction 3/4, the numerator is the 3.
Before video, ask students to write down as much as they know about fractions and using them. Listen to their ideas and write them on the whiteboard and discuss.
This is a millionaire game where students get to practice multiplying fractions.
Students play a soccer game to practice their division skills.
This is a fruit activity that helps students work with fractions that they subtract from one another.
Students play a race car game that integrates adding fractions.
Linked is a Prezi that discusses how fractions relate to every day life when we are out shopping.
Ask students if they can brainstorm ways that fractions are important or are a part of their daily lives.
School age children discuss real life application and why we need to learn fractions.
This is a baking video that discusses how we use fractions every day when baking.
Link attached to assessment that can be printed for students.
