Multiply and divide any positive integer up to 10 000 by 10 or 100 and

understand the effect.

UNIT 1UNIT 1

Multiply & Divide by 10, 100, 1000

Learning IntentionLearning Intention

1. To understand how to multiply and divide decimal numbers by 10, 100, 1000.

Success CriteriaSuccess Criteria

1.1. Understand the simple rules to Understand the simple rules to multiply and divide decimal multiply and divide decimal numbers.numbers.

2.2. Be able do calculations.Be able do calculations.

Level E

DecimalsDecimals

DiscoveringTimeSunday, 30 August 2009

3.3. To understand the effect.To understand the effect.

ten

thousands

thousands

hundreds

tens

units

The effect of multiplying a number by 10, 100, 1000 & 10000

6x10 6 0

6 06x1000 0 0

6x10000 6 0 0 0 0

66x1

06 06x100

What is happening ?

six

sixty

six hundred

six thousand

sixty thousand

Dec

imal

poi

nts

tenths

units

The effect of dividing a number by 10, 100, 1000 & 10000

What is happening ?

thousandths

hundredths

7 nought point seven

0 0 7

7

70

7 1

7 10

7 100

7 1000

0

0

0 nought point nought nought seven

seven

nought point nought seven

Level E

thousands unitstenshundreds

2 4 6 x 10

Multiplying a whole number by 10

2 4 x 106

2 4 6 0

all digits move one place to the left

Example

add place holder zero to the units column

246 x 10 = 2460

=

Level E

thousands unitstenshundreds

Multiplying a decimal by 100

6 2 x 1009

2 9 4 0

all digits move two places to the left

Example

add place holder zeros to the units columns629.4 x 100 = 62940

=

6 2 9 4 x 1 0 0

ten thousands

6

Level E

Decimal point

tenths

4

Multiply & Divide by 10, 100, 1000Level E

DecimalsDecimals

DiscoveringTime Sunday, 30 August 2009

To multiply a decimal number by 10, Simply move all digits 1 place to the left:

e.g. 2.55 x 10 = 25.5 digits are moved 1 place to left

To multiply a decimal number by 100, Simply move all digits 2 places to the left:

e.g. 1.02 x 100 = 102.0 digits are moved 2 places to left

Multiply & Divide by 10, 100, 1000Level E

DecimalsDecimals

DiscoveringTime Sunday, 30 August 2009

To multiply a decimal number by 1000, Simply move all digits 3 places to the left:

e.g. 34.567 x 1000 = 34 567 digits are moved 3 places to left

thousands unitstenshundreds

Multiplying a whole number by 100

9 3 x 1005

3 5 0 0

all digits move two places to the left

Example

add place holder zeros to the units & tens columns

935 x 100 = 93500

=

9 3 5 x 100

ten thousands

9

Level E

thousands unitstenshundreds

Multiplying a decimal by 100

4 3 x 1001

3 1 7 0

all digits move two places to the left

Example

add place holder zeros to the units columns431.7 x 100 = 43170

=

4 3 1 7 x 1 0 0

ten thousands

4

Level E

Decimal point

tenths

7

tenthsunitstenshundreds

Dividing a whole number by 10

8

all digits move one place to the right

Example

= 7

786 10 = 78.6

Decimal point

607 8 106

786 10

Level E

Decimal point

hundredthstenthsunitstenshundreds

Dividing a whole number by 100

8

all digits move two places to the right

Example

= 7

786 100 = 7.86

6

786 100

07 8 1006 0

Level E

As the following numbers appear multiply them by 10.

1.4 1.92 6.75 12.82 0.638

As the numbers appear multiply by 100.

1.56 2.50.67 8.324 16.8

Sunday, 30 August 2009

Level E

Plenary