Division Strategies

Division Strategies – We will begin learning about division this week.  Division is when you take a whole, big group of objects and break them into smaller, equal-size groups.  We will start by learning about some important strategies we can use when we want to divide.

Number of Equal Groups – When dividing, one strategy is to take the whole group and break it into smaller equal-size groups.  Then, you can count how many groups you made.

For example, if you want to solve the problem 24 / 6 you could make groups of 6 until you get to 24 and count how many groups you made:

XXXXXX          XXXXXX               XXXXXX                  XXXXXX

In this example, I have made groups of 6 and there are 24 X's in all.  When I count how many groups I have made, I count 4 groups.  So, 24 / 6 = 4.

Size of Equal Groups – A second strategy is to make your groups first, then share the whole group of objects into the smaller groups so that each group has the same amount of objects.  Then, you can count how many objects are in each group.

In this strategy, you will make a number of equal groups and share the objects into each group.  Then, you will count how many objects are in each group.  So, if you want to solve 24 / 6, you would make 6 groups and share the 24 objects equally into each group:

XXXX     XXXX      XXXX       XXXX      XXXX      XXXX

In this example, I have made 6 groups and shared the 24 objects equally into each group.  When I count how many are in each group, I find that there are 4 in each group.  So 24 / 6 = 4.

Here's a video about division and equal groups:

Repeated Subtraction – In multiplication, we learned that we could use repeated addition to solve multiplication problems.  In the same way, you can use repeated subtraction to solve division problems.  You can start with the total number and keep subtracting the same number until you have 0 objects left.  Then, you can count how many times you subtracted.

In repeated subtraction, you just keep subtracting the smaller number from the larger number until you have 0.  Then, you count how many times you subtracted.  So, if you want to solve 24 / 6 you would start with 24 and keep subtracting 6 until there are 0 left:

24 - 6 = 18
18 - 6 = 12
12 - 6 = 6
6 - 6 = 0

In this example, I subtracted 6 each time until there were 0 left.  When I count how many times I subtracted, I find that I subtracted 4 times.  So, 24 / 6 = 4.

Here's a short video that shows repeated subtraction:

Arrays – We learned about arrays in multiplication.  You can also use arrays when dividing.  When dividing, you take the whole number of squares or circles and you can either make a number of rows with the same amount in each row, or you can make rows with a  certain number in each row and keep making rows until there are none left.

When you make an array for division, you start with the whole group of objects and either fill in by rows or by columns.  So, if you want to solve 24 / 6:

These are my 24 objects:

XXXXXXXXXXXXXXXXXXXXXXXX

Now, I can make an array in two different ways.  First, I can make rows of 6 until I have 24:

XXXXXX
XXXXXX
XXXXXX
XXXXXX

Then, you count how many rows you made.  In this case, I made 4 rows so 24 / 6 = 4.

Second, I can make 6 rows and fill them in until I have 24 in all:

XXXX
XXXX
XXXX
XXXX
XXXX
XXXX

Then, you count how many are in each row.  In this case, there are 4 in each row, so 24 / 6 = 4.

Multiplication – If you know your multiplication facts (keep studying them!), you can use your multiplication facts to help you figure out division facts.

In this strategy, you can use your multiplication facts to solve division problems.  So, if you want to solve 24 / 6:

24 / 6 =           

When I look at 24 / 6, I see the numbers 24 and 6.  When I think about my multiplication facts, I know a fact that has 24 and 6 in it.  The multiplication fact is 6 X 4 = 24.  The three numbers in that fact are 6, 4, and 24.  When I go back to the division fact 24 / 6, I see that it has the numbers 24 and 6.  It is missing the 4.  So, 24 / 6 = 4.

Here's a short video about using multiplication and division facts:

Energy

Energy

What is energy?

Energy is the ability to cause change or do work.  If something changes, energy is being used.  If you are doing work, energy is being used.  Here's a short video:

Forms of Energy

There are many different forms of energy.  Light energy, heat energy, electrical energy are three common forms of energy.  Sound energy is also another type of energy.

Heat can be produced by rubbing objects together

Heat energy is one form of energy.  Heat energy can be produced in different ways.  One way to produce heat energy is by rubbing objects together.  Friction is when two objects rub together.

There are two other ways to produce heat energy.  Burning and Mixing are the two other ways to produce heat energy.

Light travels in straight lines

Light is another form of energy.  It is important to know that light energy always travels in straight-line paths.  Light energy always moves from one place to another in a straight line.

Light also gives off heat

Another important thing to know about light energy is that light energy also gives off heat energy.  If you have ever put your hand close to a light bulb, you know that the bulb feels hot.  It feels hot because the light energy is also giving off heat energy, which you feel as the warmth of the bulb.

Light can be reflected, refracted, and absorbed

Finally, light can be reflected, refracted, or absorbed.

Reflection is when light hits an object and bounces back off the object and in the direction it came from.

Refraction is when light changes direction.  This usually happens when a beam of light goes through water.  It changes its direction a little bit.  This makes objects look different if you look at them through water.

Absorption is when light goes into an object.  Some light energy hits an ojbect and goes into it.  This is why objects have color.  If an object looks green, the green part of light went into that object.  If an object looks red, the red part of light went into the object.

Story Structure

Story Structure

Story structure is the different parts of a story.  We have learned about several important parts to any story:  characters, setting, plot, problem, and solution. 

The characters are the people or animals that the story is about.  When you read, you should read to find out what the characters look like and what they do in the story. 

Setting is when and where the story takes place.  When you read, you should try to figure out when and where the characters are throughout the story. 

Plot is the important events that happen in a story.  When you read, you should pay attention to all the events that are happening in the story and decide which events are most important. 

The problem is what the main character tries to fix in the story.  When you read, you should try to figure out what problem the main character is trying to solve. 

The solution is how the main character finally is able to solve the problem.  When you read, you should look for what the character does to finally solve the problem and how it works. 

When you read a story, it is important to closely pay attention to the characters, setting, plot, problem, and solution.  Knowing these parts of a story will make it easier for you to understand what is happening in the story.

Here's a short video about story structure:

Combinations

A Combination is the joining of two or more things.  In class, we practiced making combinations  with outfits and ice cream.

Outfit Combinations:

When you get dressed in the morning, you practice using combinations.  You chose one each of a top and a bottom.  You open your closet and look at all your tops.  There are t-shirts and collared shirts and the shirts are different colors.  You choose one top and put it on.  Then, you look at the bottoms.  There are pants and shorts (and skirts if you're a girl!).  You choose a bottom and put it on.  You have just made a combination!

Ice Cream Combinations:

When you go to the ice cream shop and order some ice cream, you practice combinations.  First, you have to decide what you want your ice cream served in.  It can be served in a bowl or a cone.  Then, you have to choose the flavor of ice cream that you want.  Then, you have to choose any toppings you want on top of your ice cream.  You go up to the counter and look over the choices.  You decide that you want your ice cream in a cone, you want it to be chocolate ice cream, and you want sprinkles on top of it.  You have just made a combination!

Sometimes it is useful to know how many combinations are possible, and you can use multiplication to do it.

Let's go back to the Outfits Combinations from above.  Let's say you have these choices:

Tops                              Bottoms

Green T-Shirt                 Tan Pants
White T-Shirt                 Tan Shorts
Green Collared Shirt       Tan Skirt
White Collared Shirt

In this case there are 4 choices for a top and 3 choices for a bottom.  So, you can multiply 4 X 3 = 12 to find the total number of combinations.  There are 12 total combinations.  Let's look at why that works:

You can match the Green T-Shirt with the Tan Pants, the Tan Shorts, and the Tan Skirt.  That makes 3 combinations.  You can match the White T-Shirt with the Tan Pants, the Tan Shorts, and the Tan skirt.  That makes 3 combinations.  You can match the Green Collared Shirt with the Tan Pants, the Tan Shorts, and the Tan Skirt.  That makes 3 combinations.  You can match the White Collared Shirt with the Tan Pants, the Tan Shorts, and the Tan Skirt.  That makes 3 combinations.  So, you made 3 combinations and you did it 4 times.  3 X 4 = 12.

Here's a short video about Combinations:

In the video, she has 3 hats and 3 shirts.  If you multiply 3 X 3 = 9 you get 9 total combinations.  This is how many combinations they came up with in the video.