Fraction Action

By using words, charts, numbers, pieces of paper or other models and/or anything else you can think of…

Prove or Disprove the following:

1/2 + 1/3 = 2/5

Try this out with your child and see what they come up with!!

Visit Scholastic

Can't visit the Book Fair at school? You can still support the Chets Creek Book Fair by purchasing books from Scholastic using the link below :)

http://bookfairs.scholastic.com/bookfairs/cptoolkit/publish/chetscreek

The last day for the online Book Fair is October 10th.

Secret Message

*Get to know your PLANNER and use it as a great resource.

If you have read my Math page on our 5th grade website, write the words: "Math Rules" in your child's Planner in the "Comment Section". Students know to put any notes in the apple box. I wonder how many planners I will see!!

Compitable Numbes are Easy to Compute Mentally

Compatible Number Division Problems:

We like to call Compatible Numbers numbers that "get along" with each other, much like compatible people. In math, we're talking about one number that is easily divisible by another number. These numbers are useful for determining an estimate of the actual answer to a division problem. You will see three different types of Compatible Number problems in homework and on tests:

Type 1: 3792 ÷ 6 = n

The divisor in this problem is 6. Because we know the multiples of 6 without having to work them out, we want to make the dividend (3792) into a number that "gets along" or works easily with the divisor 6. We know that the two largest place values create the number 3700. This number is not a multiple of 6, but 3600, which is very close, is. In this case, we would round the dividend to 3600 and keep the divisor 6 as it is:

3600 ÷ 6 = n
This problem is quickly solved when we use the inverse operation, multiplication: 6 x 6 = 36, so 6 x 600 = 3600.

The actual answer to this problem is 632, so our estimate of 600 is reasonable.

Type 2: 3792 ÷ 60 = n

Much like the problem above, the divisor, 60, is easy to use. Since we know the multiples of 6 without having to work them out, we can also determine the multiples of 60 without much effort. Again, we will keep the divisor the same and round the dividend to the nearest landmark multiple of 60.

3600 ÷ 60 = n

Using the inverse operation, we know that our estimate would be

60 x 60 = 3600.

The actual answer to this problem is 63.2, so our estimate of 60 is reasonable.

Type 3: 3792 ÷ 63 = n

In this problem, we do not readily know the multiples of 63. In this case, we must first round the divisor 63 to the nearest landmark number, which is 60. Now, we can look at the dividend to think of a landmark multiple of 60 that is close to 3792. Of course, the number would be 3600. Using the inverse operation, we can quickly determine an estimate for our actual problem:

60 x 60 = 3600

Again, our estimate would be 60. Since the actual answer is 60.19. Our estimate is very close to the actual answer.

Chet the Eagle

We have a new school blog that is being written by Chet the Eagle. Chet is going to help us highlight some school wide events and positive happenings that go on every week. Parents and kids are encouraged to leave comments for Chet. This is a great way to access photos from school events.

http://cheteagle.blogspot.com

Split It

Split It

This is an easy strategy to split a number like 7,758 in half.

What I look for is a way to make splitting the number easy by using simple mental calculations. Usually, the first step is to decompose the number into its place values. So, 7,758 becomes

7,000 + 700 + 50 + 8 .

Then, I ask that a student rewrite any number that they cannot readily split. Usually, these numbers start with odd numbers. We'll look at 7,000.

7,000 could be rewritten as 6,000 +1,000 (both of which are easy to split).

After that, it's all down hill.

The whole number could be rewritten as
6,000 + 1,000 + 600 +100 + 40 + 10 +8,

and finding half of these numbers should be EZ!
3,000 +500 +300 + 50 +20 +5 +4 = 3,879!

Try it!!

Power Tower

Here's how to build a Power Tower:
A Power Tower is a list of the first nine multiples of a number, which can be very helpful when beginning multi-digit division. To be super efficient, there is a strategic way to build the tower so that it doesn't take much time. Here's the top secret strategy:

Example: Let's build a Power Tower for 37 so that we can solve the problem 2886 divided by 37.

1 - 37 (This is the number we are dividing by)
2 - 74 (Double the first multiple, 30 + 30 = 60; 7 + 7 = 14; 60 + 14 = 74)
3 - 111 (The sum of the first 2 multiples, 30 + 70 = 100; 7 + 4 = 11; 100 + 11 = 111)
4 - 148 (Double the second multiple, 70 + 70 = 140; 4 + 4 = 8; 140 + 8 = 148)
5 - 185 (Split the tenth multiple in half, 37 x 10 = 370; 1/2 of 300 = 150; 1/2 of 70 = 35;
150 + 35 = 185)
6 - 222 (Double the third multiple, 100 + 100 = 200; 10 + 10 = 20; 1 + 1 = 2; 200 + 20 + 2=
222)
7 - 259 (The sum of the sixth and first multiples, 222 + 30 = 252; 252 + 7 = 259)
8 - 296 (Double the fourth multiple; 140 + 140 = 280; 8 + 8 = 16; 280 + 16 = 296)
9 - 333 (The sum of the eighth and first multiples, 296 + 30 = 326; 326 + 7 = 333)

Note: Complete the green multiples first, the orange second, the red third, and the blue last.

Looking at our tower, we know that the 7th multiple of 37 is 259, so the 70th multiple will be 2590. This is the closest we can get to 2886 without going over, using a landmark multiple of 37. The difference in 2886 and 2590 is 296. Looking at our Power Tower, we can see that the 8th multiple of 37 is 296. So, 2886 divided by 37 equals 70 + 8 = 78.

Entertainment Books - PTA Fundraiser

Entertainment Books - PTA Fundraiser

Everyone should have received their book this week. The sale of these books goes through September 9th. 50% of the sales goes directly to your PTA to help sponsor anti-bullying programs, Internet Safety training, and other activities all year long.

All books that are not sold should be returned to your student's teacher by Monday, September 12th. All orders placed will be filled & returned to your student promptly. If they are large & too heavy for the child to carry, we will notify you of their availability so that you can stop in to pick up the books for your customers.

Thank you for your support.

Great Common Factor

Greatest Common Factor

Our math class is learning about GCF. Here is some information that will help.

The highest number that divides exactly into two or more numbers.
It is the "greatest" thing for simplifying fraction (putting fractions in lowest terms)!

Greatest Common Factor is made up of three words

• Greatest,
• Common and
• Factor

What is a "Factor" ? Factors are the numbers you multiply together to get another number:

2 X 3 = 6 2 and 3 are factors

Sometimes we want to find ALL the factors of a number:

The factors of 12 are 1,2,3,4,6 and 12 ... because 2 × 6 = 12, or 4 × 3 = 12, or 1 × 12 = 12.

What is a "Common Factor" ? Let us say you have worked out the factors of two or more numbers:

The factors of 12 are 1, 2, 3, 4, 6 and 12

The factors of 30 are 1, 2, 3, 5, 6, 10, 15 and 30

Then the common factors are those that are found in both numbers:

• Notice that 1,2,3 and 6 appear in both lists?
• So, the common factors of 12 and 30 are: 1, 2, 3 and 6

It is a common factor when it is a factor of two or more numbers. (It is then "common to" those numbers.) Example: What are the common factors of 15, 30 and 105?

The factors of 15 are 1, 3, 5, and 15

The factors of 30 are 1, 2, 3, 5, 6, 10, 15 and 30

The factors of 105 are 1, 3, 5, 7, 15, 21, 35 and 105

The factors that are common to all three numbers are 1, 3, 5 and 15

In other words, the common factors of 15, 30 and 105 are 1, 3, 5 and 15

What is the "Greatest Common Factor" ? It is simply the largest of the common factors. In our previous example, the largest of the common factors is 15, so the Greatest Common Factor of 15, 30 and 105 is 15

The "Greatest Common Factor" is the largest of the common factors of two or more numbers

Why is this Useful? One of the most useful things is when we want to simplify a fraction:

Example: How could we simplify ¹²/₃₀ ?

At the top we found that the Common Factors of 12 and 30 were 1, 2, 3 and 6, and so the Greatest Common Factor is 6.

This means that the largest number we can divide both 12 and 30 evenly by is 6, like this:

12 ÷ 6 = 2

30 ÷ 6 = 5

The Greatest Common Factor of 12 and 30 is 6. And so ¹²/₃₀ can be simplified to ²/₅

Finding the Greatest Common Factor Here are three ways:

1. You can:

• find all factors of both numbers (All Factors Tool to help you),
• then select the ones that are common to both, and
• then choose the greatest.

Example:

Two Numbers	All Factors	Common Factors	Greatest Common Factor	Example Simplified Fraction
9 and 12	9: 1,3,9 12: 1,2,3,4,6,12	1,3	3	9/12 » 3/4

And another example:

Two Numbers	All Factors	Common Factors	Greatest Common Factor	Example Simplified Fraction
6 and 18	6: 1,2,3,6 18: 1,2,3,6,9,18	1,2,3,6	6	6/18 » 1/3

2. You can find the prime factors and combine the common ones together:

Two Numbers	Thinking ...	Greatest Common Factor	Example Simplified Fraction
24 and 108	2 × 2 × 2 × 3 = 24, and 2 × 2 × 3 × 3 × 3 = 108	2 × 2 × 3 = 12	24/108 » 2/9

3. And sometimes you can just play around with the factors until you discover it:

Two Numbers	Thinking ...	Greatest Common Factor	Example Simplified Fraction
9 and 12	3 × 3 = 9 and 3 × 4 = 12	3	9/12 » 3/4

But in that case you had better be careful you have found the greatest common factor.

Math Rules!!