Objectives: Understand and use decimal place value. Multiply and divide by 10 and 100 and explain the effect. Vocabulary.

Objectives:

• Understand and use decimal place value.

• Multiply and divide by 10 and 100 and explain the effect.

Vocabulary

Multiply this number by 10

What is your answer?

What has happened to all of the digits?

What happens when we multiply by 100?

T U

H T U

3 tens become 3 hundreds, 5 units become 5 tens

Each digit in the number has moved one column to the left.

(each digit in the number moves 2 columns to the left)

Th H T U

H

Multiply each of the following numbers by 10, as they appear.

Multiply each of the following numbers by 100, as they appear.

230 560 1230 400

3500 2000 21300 34 000

Divide this number by 10

What is your answer?

Explain what has happened to each of the digits.

What happens when we divide by 100?

T U

U . t

The 4 tens become 4 units, the 6 units become 6 tenths.

Each of the digits in the number has moved one column to the right.

Each of the digits in the number moves two columns to the right.

U . t h

. t

Divide each of the following numbers by 10, as they appear.

Divide each of the following numbers by 100, as they appear.

5.7 13.4 35.0 7.0

4.503.9 4.09 0.50

400 3 30 500

1000 70 9 40

20 50 200 8

300 5 60 700

T1.1B

As the number is highlighted multiply or divide by powers of 10 as instructed.

30 3

0.3 3 3000

30000 300

X ?X ?

X ?

X ?

X ?X ?

3 x 1 = 3

3 x 1000= 3000

3 x 100 = 3003 x 10 000 = 30 000

3 x 10 = 30

3 x 0.1 = 0.3

Look carefully at this spider diagram before you move on.

Multiplication Spider DiagramW/S1.1B

Using worksheet W/S 1.1B complete your own multiplication spider diagram. Choose your own number in the middle.

Now check your answers using a calculator.

465

÷ 10÷ 100

÷ 1

÷ 1 000

46.5

0.465

465

4.65

Try to state the answer before it appears on the spider diagram.

W/S 1.2BDivision Spider Diagram

Start with a number of your choice in the middle and complete the division spider diagram.

Now check your answers on a calculator before you move on.

0.3 30 6 40

400 5 0.6 0.5

50 4 300 0.4

3 500 60 600

T1.2B

I divided by ten and my answer is 0.6 – what number did I start with?

I multiplied by 100 and my answer is 40 – what number did I start with?

Make up three questions like the ones above and try them out on someone else – explain your working to them if necessary.

Objectives:

• Understand and use decimal place value.

• Multiply and divide by 10 and 100 and explain the effect.

Vocabulary

Thank you for your attention