Decimals
PLACE VALUE OF DECIMALS
We use the decimal point to separate whole numbers from parts of
numbers (the decimal numbers)
This happens when we use money
decimal point

£2.57
 
2 whole pounds
the pence are parts
of a whole pound.
£0.57 is 57 parts of 100.
and it happens when we use other decimal numbers
decimal point

12.77
 
The whole number
is before the point
the decimal number
is after the decimal point
You would write this in words as Twelve point seven seven
A
Have a go at writing these in numbers. The first 2 are done for
you.
Seven point three
= 7.3
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Twenty two point eight five = 22.85
1)
Five point five
2)
Twelve point one
3)
Twenty point six two
4)
Nine point three nine
5)
Eleven point one seven five
6)
Fifty point five
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Decimals
B
Now have a go at writing these in words. The first 2 are
examples.
7.4
=
Seven point four
6.35
=
Six point three five
1)
9.1
2)
23.84
3)
30.4
4)
3.04
5)
2.99
6)
1.04
Whole numbers have place value.
thousands
1000’s
hundreds
100’s
tens
10’s
units
1’s
.
get ten times bigger
So do decimals
Whole numbers
10’s
tenths
1
10
1’s
hundredths
1
100
thousandths
1
1000
.
get ten times smaller
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All numbers get
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10 times bigger as you move to the left,
and 10 times smaller as you move to the right.
2
Decimals
Each number in a decimal is worth an amount.
10’s
tenths
1
10
1’s
7
10’s
1’s
7
0
.
.
hundredths
1
100
1
3


1
10
3
100
tenths
1
10
hundredths
1
100
3
7
5



3
10
7
100
5
1000
thousandths
1
1000
Remember
The point separates the whole numbers from the decimals.
Numbers get 10x bigger as you go left and
10x smaller as you go right.
C
Try these yourself
1
Underline the 10 ‘s in these numbers.
1)
1.57
0.176
26.3
107.75
22.07
9.9967
0.06
1
Underline the 100 ‘s in these numbers.
2) 7.25
0.375
113.92
How much is the 3 worth on these numbers?
3) 3.5
0.37
0.23
26.3
How much is the 7 worth on these numbers?
4) 17.62
0.87
10.71
0.007
70.45
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Check your answers, then discuss with your tutor what you need to
work on next.
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Decimals
Answers
Place Value Of Decimals
A
1)
5.5
2)
12.1
3)
20.62
4)
9.39
5)
11.175
6)
50.5
B
1)
Nine point one
2)
Twenty three point eight four
3)
Thirty point four
4)
Three point nought four (or Three point zero four)
5)
Two point nine nine
6)
One point nought four (or One point zero four)
C
1)
1.57
0.176
26.3
107.75
22.07
2)
7.25
0.375
113.92
9.9967
0.06
3)
Three units
3
3
Three tenths 10
Three hundredths
3
100
3
Three tenths 10
4)
Seven units
7
Seven hundredths
7
100
7
Seven tenths 10
Seven thousandths
7
1000
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Seventy (seven 10's) 70
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