Subtracting Integers

Scared of subtraction involving negative integers? Don't be - remember, it's just addition in disguise!

The rule for subtraction is:

Add the OpPoSiTe!


Who likes fried chicken? It's one of my all-time favorites. :)

Img: thebittenword.com

So... what does fried chicken have to do with subtracting integers? Check out this cool chart from passyworldofmathematics.com:


Then, solve your problem as an addition problem. Here are a few examples:

-5 - 3 = ?
-5 + (-3) = -8  ---> Both numbers are the same sign, so we can add like normal and keep the sign.

7 - (-2) = ?
7 + 2 = 9   ---> Again, both numbers are the same sign, so we can add like normal and keep the sign.

4 - 8 = ?
4 + (-8) = ?  ---> Now we've got addition with two different signs, so remember to use your absolute values!
The absolute values are 4 and 8. The difference between 4 and 8 is 4. Now, is it negative or positive? Look at the original number that had the greatest absolute value: -8. Since it's negative, we know the answer is -4.

If you are self-checking subtraction of integers tonight, here are the answers to the Quick Checks from 1-6 (pgs. 30 & 31):

1) a. -5
    b. -1
    c. -3

2) a. -4
    b. -6
    c. 5

3) a. 35
    b. -106
    c. -46

HaPpY SuBtRaCtInG!

Study Guide

Greetings, Mathlings! Here's a very quick, to-the-point study guide for your assessment on Tuesday. The test will cover all fractions operations. Some quick rules to remember:

Adding fractions:

- Make sure the fractions have like denominators before you add. This can be done by finding the LCD or  by using the butterfly method. 

- Once the fractions have the same denominator, add the numerators and keep the denominator the same. Then, simplify if necessary. 

- If one of the numbers is a mixed number, add the whole numbers separately from the fractions, and then combine. 

Subtracting fractions:

- Again, make sure the fractions have like denominators before you subtract This can be done by finding the LCD or  by using the butterfly method. 

- Once the fractions have the same denominator, subtract the numerators and keep the denominator the same. Then, simplify if necessary. 

- If one of the numbers is a mixed number, subtract the whole numbers separately from the fractions, and then combine. 

Multiplying fractions:

- Multiply straight across - the numerators and the denominators. 

- You may simplify before you multiply OR after. 

- If one of the numbers is a mixed number, first convert it to an improper fraction before you multiply. 

Dividing fractions:

- Keep, flip, change:

1. Keep the first fraction the same. 

2. Flip the operation to multiplication instead of division. 

3. Change the second fraction to its reciprocal. 

- After KFC, use the method for multiplication. 

Hehehe

Just a reminder that tomorrow you'll be taking a very quick open-note quiz on multiplying fractions/mixed numbers. A few things to remember:

- Multiply the numerators and denominators, and then simplify
- You may simplify before you multiply if you choose
- To multiply with a mixed number, first change the mixed number to an improper fraction; then, multiply

Side note, this is probably my favorite photobomb of all time:

Merry Christmas!!!

I hope you all have a wonderful time with family this holiday! Merry Christmas!

<3, Ms. J & Bucky

Quiz Tomorrow!

Hello mathlings! This is just a reminder that tomorrow's quiz is going to include the following concepts:

Greatest Common Factor (GCF)

Least Common Multiple (LCM)

Equivalent Fractions

Simplest Form

Comparing and Ordering Fractions

Please study your notes tonight. You will need to use prime factorization to find both the GCF and LCM for some of the problems. A few reminders:

* When finding the GCF through prime factorization, the common factor that "matches" MUST be found in ALL of the numbers you are breaking down.

* When finding the LCM through prime factorization, the common factor that "matches" needs only to be found in TWO of the numbers you are breaking down to be considered a match and used once. It does not need to be found in all of the numbers you're breaking down.

* In order to compare and order fractions, all of the fractions must have the same denominator. Then, compare using the numerators. In order to change the fractions to equivalent fractions with the same denominator:

1. Find the Least Common Denominator (LCD).
2. Change the fractions to equivalent fractions using the LCD.
3. Ask: How could I get from my original denominator to the new denominator? Then, multiply the numerator by whatever you would multiply the denominator.

Again, please, please, please study your notes! We take them for a reason :) Good luck and happy studying!

Infographic

Here's a great infographic from Long Beach Unified School District that illustrates how to turn a mixed number into an improper fraction:

Circumference Visuals

Hey everyone! We will be reviewing circumference tomorrow. Here are some visuals for study (source: WikiHow):