An Array a Day

Mrs. Amatangelo

A ray is what you learn about in geometry. This is a ray.

A B

This is NOT an ARRAY.

Next

A ray gun.

A stingray.

A ray of sunshine.

These are rays:

They are NOT ARRAYS.

Ray from Ghostbusters

An X-ray Next

An

is when you make rows and columns.

ARRAY

Next

Arrays are all around you.

Next

Next

Next

Draw the array and label its dimensions.An array with the dimensions of 6 by 2 would look like this:

To label the dimensions, write a 2 to show 2 columns, and a 6 to show 6 rows.

2

6

or for a 2 by 6, like this:

Next

An

is when you make rows and columns.

ARRAY

Back

Dimensions means how many rows and how many columns

Back

Label means to write the number that shows how many are in each row and column.

Back

Write a multiplication sentence:

There are 6 rows of 2 so the

multiplication sentence is:

6 * 2 = 12

2

6

Next

What does it mean?

The multiplication sentence

6 * 2 = 12

means

there are

6 rows

with

2 in each row.

2

6

Next

Write a division sentence.

12 / 6 = 22

6

Next

What does it mean?

Take 12 squares and put them into

6 groups with

2 in each group.

2

6

Next

What is the area?

The area is:

how many squares

are inside the shape.

2

6How much carpet would I need if I covered the floor with carpet instead?

How many tiles do I need to cover a floor?

Next

What is the area?

There are 12 squares inside the shape,

so the area is 12 squares.

2

6

Next

What is the area?

To find the area,

multiply the number of rows

by the number of columns.

6 * 2 = 12

2

6

Next

What is the perimeter?

The perimeter is how many units surround

the shape.

2

6 6

2

Next

What is the perimeter?

It’s like the fence that goes around the outside of the

shape.

2

6 6

2

Next

What is the perimeter?

The question, “What is the

perimeter?” is asking,

How long is the fence that goes

around the outside of the

shape?

2

6 6

2

Next

What is the perimeter?

2

6 6

2

This ‘fence’ is

6 squares long

and

2 squares wide,

with

6 more squares long,

and

2 more feet wide. Next

What is the perimeter?

To find the perimeter, add

all the lengths

and

all the widths of the sides.

6+2+6+2=16

The perimeter is

16

2

6 6

2

Next

List all the factors of the area.

1, 2, 3, 4, 6, 12

are the factors of the area 12,

because:

1 * 12 =12

2 * 6 = 12

3* 4 = 12 Next

List means to write as many as you can think of.

Back

Factors = the numbers you multiply to get a product

Back

Product = the answer you get when you multiply

Back

List all the factors of the area.

1 and 12

are factors of the area 12,

because:

1 * 12 = 12

12

1

Next

List all the factors of the area.

3 and 4

are the factors of the area 12,

because:

3 * 4 = 12

4

3

Next

List all the factors of the area.

2 and 6

are factors of the area 12,

because:

2 * 6

Next

List all the factors of the area.

The factors are the same numbers you used to find the area.

(length * width = area)

Next

Is the area prime or composite?

Prime = the area has only two factors: 1 and itself

Composite = the area has more than 2 factors

Next

Prime1

11

11

1

A shape with an area of 11 is prime. The only numbers you can multiply to get 11 are 1 and 11.

1x11=11

Next

Some other prime arrays are:1

7

3

2

1

1

1

135

1

Back

Composite

A shape with the area of 12 is composite because 12 has more than 2 factors.

Next

12

12

6

4

3

3

4

6

2

1

12

Back

Repeated Addition

2+2+2+2+2+2=12

+ + + + +

Next

Draw additional arrays with the same area and label their

dimensions.

Next

12

12

6

4

3

3

4

6

2

1

12

Next

Additional: more of the same thing

Label: write the numbers to show what it means

Dimensions: the size

how big it is

the length and the width

Next

So what?• How large of an area do we need for every student to sit at a

desk? • How many 25 student classes will fit in an area the size of

the floor in the multi-purpose room?• How much newspaper do I need to cover an area the size of

the ceramics table?• How much paint do I need to cover an area the size of the

walls in my room?• If one student needs a 9 foot square area to jump rope, how

large of an area would 25 students need?• The swings need a mat under them. How large should the

mat be to cover the area under the swings?• 5 friends brought their sleeping bags to a sleepover. If every

sleeping bag covers a 12 foot area, what size tent should we use?

• Each family member rakes the leaves from a 100 square foot area. How many family members are needed to rake a yard with a 1000 square foot area?

Next

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