NUM 13-Jan-16Created by Mr. Lafferty Maths Dept. Decimal Numbers What is a decimal ? Decimal Scales ...
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Transcript of NUM 13-Jan-16Created by Mr. Lafferty Maths Dept. Decimal Numbers What is a decimal ? Decimal Scales ...
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Decimal Decimal NumbersNumbers
What is a decimal ?
Decimal Scales
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Dividing by 10, 100, 1000
Multiplying by a single Digit
Rounding
Addition and Subtraction
Multiplying by 10, 100, 1000
Dividing by a single Digit
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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1. Find the missing value
2. Calculate of 6000
3. What is the next three numbers in the sequence 9, 15, 21, 27, ...., ...., .... 4. Round 72 to the nearest 10
3 ?=4 20
20%
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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1.1. Understand what a decimal Understand what a decimal number is.number is.
1. We are learning what a decimal number is. Write down the decimal number represented by a fraction diagram.
Decimal Decimal NumbersNumbers
2.2. Write down the decimal Write down the decimal number represented by a number represented by a fraction diagram.fraction diagram.
Writing Decimals
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
When you take a When you take a single unitsingle unit and divide it and divide it into 10 bitsinto 10 bits, , what we then have are what we then have are
decimal fractionsdecimal fractions of a whole number of a whole number
Writing Decimals
Imagine, 1 bar of chocolate as our UNIT of measure.
1 (of 1 bar)
10
or 0.1
1
0.110 1. 0
0.1 0.40.2 0.3 0.5
0.6 0.90.7 0.8 1.0
means ten
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Writing Decimals
Example : Write down the decimal number represented by the shaded area.
(a)
(b)
0.3
3 "which means 3 tenths = "
10
0.5
5 1 "which means 5 tenths = = "
10 2
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Writing Decimals
Example : Write down the decimal number represented by the diagram.
(a) (b)
(c) (d)
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
We can take one bit of the chocolate bar We can take one bit of the chocolate bar and split it into 10and split it into 10
Writing Decimals
0.10.01
1st Decimal place
2nd Decimal place
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Writing Decimals
Example : Write down the decimal number represented by the diagram.
(a) (b)
(c) (d)
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 1
Ch2 (page 9)
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Decimal Decimal NumbersNumbers
Writing Decimals
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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.com 1. Find the perimeter of the shape
2. Calculate 30% of 900
3. Find the area of the rectangle
6cm in length by 4 cm wide.
4. Name the shape.
3cm
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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1.1. Understand the steps to Understand the steps to work out any decimal scale work out any decimal scale to 2 decimal places.to 2 decimal places.
1 We are learning how to read decimal scales.
Decimal Decimal NumbersNumbers
2.2. Solve problems by working Solve problems by working out scales. out scales.
Reading Scales
NUM
21 Apr 202321 Apr 2023 Compiled by Mr. Lafferty Maths Dept.Compiled by Mr. Lafferty Maths Dept.ww
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Litres
1
2
0
How much liquid in the jug ?
going up 0.2 each time
0.8 litres
Decimal ScalesDecimal Scales
1 ÷ 5 = 0.2
NUM
21 Apr 202321 Apr 2023 Compiled by Mr. Lafferty Maths Dept.Compiled by Mr. Lafferty Maths Dept.ww
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Litres
1
2
0
How much liquid in the jug ?
1.4 litres
Decimal ScalesDecimal Scales
NUM
21 Apr 202321 Apr 2023 Compiled by Mr. Lafferty Maths Dept.Compiled by Mr. Lafferty Maths Dept.ww
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Litres
1
2
0
How much liquid in the jug ?( Careful different scale)
going up 0.25 each time
1.75 litres
Decimal ScalesDecimal Scales
1 ÷ 4 = 0.25
NUM
21 Apr 202321 Apr 2023 Compiled by Mr. Lafferty Maths Dept.Compiled by Mr. Lafferty Maths Dept.ww
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Calculate the weight each arrow is pointing at?
Decimal ScalesDecimal Scales
grams
0 1g
2g
3g
4g5g
1.2g
2.8g
5.4g
going up 0.2 each time
1 ÷ 5 = 0.2
NUM
21 Apr 202321 Apr 2023 Compiled by Mr. Lafferty Maths Dept.Compiled by Mr. Lafferty Maths Dept.ww
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Calculate the weight each arrow is pointing at?
grams
0.1
0.2
0.3
0.40.5
0.04g
0.36g
0.52g
Decimal ScalesDecimal Scales
0
going up 0.02 each time
0.1 ÷ 5 = 0.02
NUM
21 Apr 202321 Apr 2023 Compiled by Mr. Lafferty Maths Dept.Compiled by Mr. Lafferty Maths Dept.ww
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Calculate the weight each arrow is pointing at?
Kilograms
0 2
4
6
810
0.8kg
7.2kg
10.4kg
Decimal ScalesDecimal Scales
going up 0.4 each time
2 ÷ 5 = 0.4
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 2
Ch2 (page 10)
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Decimal Decimal NumbersNumbers
Writing Decimals
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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.com 1. Name the part of the circle.
2. Calculate 60% of 300
o3. I f I am f acing North and turn 90 clockwise, which direction am I f acing
4. How many lines of symmetry has the shape.
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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1. We are learning how to round to 1 decimal place.
Decimal Decimal NumbersNumbers
1.1. Remember steps to Remember steps to round round to 1 decimal place.to 1 decimal place.
Rounding to 1 decimal place
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
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8.2cm 8.3cm 8.4cm
Decimal Decimal NumbersNumbers
8.24 8.28 8.35
Rounding to 1 decimal place
Find the values of the arrows.
Is 8.24 nearer to 8.2 or 8.3 ? 8.2Is 8.28 nearer to 8.2 or 8.3 ? 8.3Is 8.35 nearer to 8.2 or 8.3 ? Neither
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
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RoundingRoundingRounding to Any Number of Decimal Places
When rounding to :
1 decimal place look at 2nd decimal figure
e.g. 2.46
e.g. 6.456
e.g. 3.7846
e.g. 13.1146
2 decimal place look at 3rd decimal figure3 decimal place look at 4th decimal figure4 decimal place look at 5th decimal figure
MNU 3-01a
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
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RoundingRoundingRounding to Any Number of Decimal Places
Example :
Rounded to 1 decimal place, the number is
4.3
4.26
4.262
4.2616
Rounded to 2 decimal place, the number isRounded to 3 decimal place, the number isRounded to 4 decimal place, the number is
MNU 3-01a
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
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RoundingRoundingRounding to Any Number of Decimal Places
Example : Use your calculator to find the answers to
62.73
Round your answers to 2 decimal places.
MNU 3-01a
134.59
4.29
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 3
Ch2 (page 12)
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Decimal Decimal NumbersNumbers
Writing Decimals
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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1. 13 x 7
2. Calculate 23 x 10
3.
4. Find the missing number
3 of 804
1, 1, 2, 3, 5, 8, ...., ...., ....
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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1. We are learning how to add and subtract decimal numbers.
1. Understand that you must keep the decimal point lined up when adding and subtracting decimal numbers.
Decimal Decimal NumbersNumbers
2. Show all working.
Add and Subtract Decimals
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Example : Calculate 7.8 + 0.92
When you add or subtract decimal numbers, it is important to line-up the decimal points.
Add and Subtract Decimals
8 7 2
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Example : Calculate 4 – 0.84
When you add or subtract decimal numbers, it is important to line-up the decimal points.
Add and Subtract Decimals
3 1 6
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Example : Find the value x cm and y cm
Add and Subtract Decimals
2.1cm3.91cm
x cmx cm y cm
y cm3.25cm
2.2cm
6 0 1 1 0 5
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 4
Ch2 (page 14)
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Decimal Decimal NumbersNumbers
Writing Decimals
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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srevis
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3. Calculate 712 - 6.7
4. Calculate the value of the missing angle.
23o
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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1. We are learning how to multiply a decimal number by a single Digit.
1. Understand how to multiply a decimal number by a single Digit.
Decimal Decimal NumbersNumbers
2. Show appropriate working.
Multiplication by a Single Digit
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
When multiplying by a single digit the decimal point always stays in line.
Example :Calculate 23.68 x 7
Multiplication by a Single Digit
1 6 5 7 6
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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6.52 x 2
Decimal Decimal NumbersNumbers
Multiplication by a Single Digit
1 3 0 4
95.05 x 5
4 7 5 2 5
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 5
Ch2 (page 16)
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Decimal Decimal NumbersNumbers
Multiplication by a Single Digit
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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2. Calculate 20% of 360
3. Calculate 72 - 58
4. Calculate the value of the missing angle.
57o
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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1. We are learning how to divide a decimal number by a single Digit.
1. Understand how to divide a decimal number by a single Digit.
Decimal Decimal NumbersNumbers
2. Show appropriate working.
Division by a Single Digit
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
When dividing by a single digit the decimal point always stays in line.
Example : Calculate 17.16 ÷ 6
Division by a Single Digit
2 8 6
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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6.37 ÷ 7
Decimal Decimal NumbersNumbers
0 9 1
75.60 x 5
1 5 1 2
Division by a Single Digit
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 6
Ch2 (page 18)
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Decimal Decimal NumbersNumbers
Division by a Single Digit
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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srevis
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1. 46 x 3
2. Find the missing value
3.
4. Calculate the value of the missing angle.
35 ?=50 10
1 of 4907
40 o
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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srevis
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.com Learning IntentionLearning Intention Success CriteriaSuccess Criteria
1.1. Understand the rules for Understand the rules for multiplying decimal numbers by 10, 100, 1000.
1 We are learning how to multiply decimal numbers by 10, 100, 1000.
2.2. Be able solve problems Be able solve problems using rules.using rules.
Decimal Decimal NumbersNumbers
Multiplying by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
To multiply a decimal number by 10, Simply move point 1 place to the right:
e.g. 2.55 x 10 = 25.5 point is moved 1 place to right
To multiply a decimal number by 100, Simply move point 2 places to the right:
e.g. 1.023 x 100 = 102.3 point is moved 2 places to right
Multiplying by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
To multiply a decimal number by 1000, Simply move point 3 places to the right:
e.g. 34.5674 x 1000 = 34567.4 point is moved 3 place to right
Multiplying by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Example : Calculate the following
22.7 x 10 69.2 x 100 0.12 x 1000
= 227 = 6920 = 120
Multiplying by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Practice
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 7
Ch2 (page 18)
ww
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Decimal Decimal NumbersNumbers
Multiplying by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Starter QuestionsStarter Questionsw
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srevis
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1. By rounding to 1 sig. fi g. estimate 28 x 76
2. Find the missing value
3.
4. Calculate the value of the missing angle.
56 ?=80 10
1 of 2464
126 o
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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srevis
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.com Learning IntentionLearning Intention Success CriteriaSuccess Criteria
1.1. Understand the rules for Understand the rules for dividing numbers by 10, 100, 1000
1 We are learning how to divide decimal numbers by 10, 100, 1000.
2.2. Be able solve problems Be able solve problems using rules.using rules.
Decimal Decimal NumbersNumbers
Dividing by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
w.m
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srevis
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Decimal Decimal NumbersNumbers
To divide a decimal number by 10, Simply move point 1 place to the left:
e.g. 89 ÷ 10 = 8.9 point is moved 1 place to left
Dividing by 10, 100, 1000
To divide a decimal number by 100, Simply move point 2 places to the left:
e.g. 199 ÷ 100 = 1.99 point is moved 2 places to left
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
To divide a decimal number by 1000, Simply move point 3 places to the left:
e.g. 35 837 ÷ 1000 = 35.837 point is moved 3 places to the left
Dividing by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Example : Calculate the following
452.4 ÷ 10 67 ÷ 100 0.86 ÷ 1000
= 45.24 = 0.67 = 0.00086
Dividing by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww
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Decimal Decimal NumbersNumbers
Practice
Dividing by 10, 100, 1000
NUM
21 Apr 202321 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.
Now try Lifeskills Ex 8
Ch2 (page 18)
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Decimal Decimal NumbersNumbers
Dividing by 10, 100, 1000
Have you updated your Learning
Log ?
Are you on Target 1 ?
I can ?
Are you on Target 2 ?
I can ?