Academic Skills Advice
Decimals Refresher Sheet 1
What do Decimal Numbers mean?
Before the decimal point you have hundreds, tens & units then after the decimal point is
tenths, hundredths, thousandths etc.
5
0
.
0
1
2
5
1
3
3
3
.
.
.
.
.
1
10
2
4
4
0
0
1
100
5
0
4
0
1
1000
Ten
thousandths
U
1’s
thousandths
T
10’s
hundredths
H
100’s
Tens
tenths
H
T
U
Thousands
Hundreds
Thousands
Ten Thousands
Hundred
Thousands
Millions
T
U
Millions
Units
H
Ten Millions
Hundred
Millions
The columns look like this:
1
10,000
9
4
In the first number there is 1 ten, 5 units, 2 tenths and 5 hundredths.
The second number has 50 thousands, 2 tens, 1 unit, 4 tenths and 9 thousandths.
The last 3 numbers look similar but notice that the first one has 4 tenths, the second has 4
hundredths and the third has 4 thousandths. The 4 has a different value depending on
which column it is in. Notice that the zero’s are important as they keep the 4 in the correct
column.
Examples:

Write the number 15 and 4 thousandths in digits:
15.004 (Put the 4 in the thousandths column and keep it there by using 0’s)

Write the number 5 and 27 hundredths in digits:
5.27 (make sure you end in the hundredths column)

In the number 238.256 what is the value of the 5?
The 5 is in the hundredths column so it’s value is 5 hundredths.
© H Jackson 2008 / Academic Skills
1
Comparing Decimal Numbers:
Remember that a number in the tenths column is worth more than one in the hundredths
column and so on. So 3.4 is bigger than 3.04 etc.
To compare decimal numbers consider one column at a time and as soon as you have a
bigger number that is the bigger number overall.
Examples:

Put these numbers in order of size: 3.42
3.395
3.6
3.45
3.417.
You might be tempted to think that the one with the most digits is the biggest but you need
to compare one column at a time.
H
T
U
.
3
3
3
3
3
.
.
.
.
.
1
10
4
3
6
4
4
1
100
2
9
5
1
1
1000
1
10,000
5
7
Compare the units column first – all 3’s so the same size so far.
Compare the tenths column next – the 6 is biggest so 3.6 is the biggest number. 3 is the
smallest so 3.395 is the smallest number. The others are all the same so far so you need
to compare the next column.
Compare the hundredths column and you can see that 3.45 is the next biggest, 3.42 is
next and 3.417 is next. You don’t need to compare the final column as it is irrelevant now
you know the order.
From biggest to smallest is 3.6 3.45 3.42 3.417 3.395.
(With practice you will be able to do this without the table.)
Another method:
H
T
U
.
3
3
3
3
3
.
.
.
.
.
1
10
4
3
6
4
4
1
100
2
9
0
5
1
1
1000
0
5
0
0
7
1
10,000
Another way to compare these numbers is to fill all the gaps (after the decimal point) with
zero’s then just compare 420, 395, 600, 450 and 417 (the numbers after the decimal point).
Now it’s easy to see the order. 600, 450, 420, 417, 395.
© H Jackson 2008 / Academic Skills
2
Practice Questions:
Write the following numbers in digits:
1) 22 and 5 tenths.
2) 74 and 7 hundredths.
3) 6 and 22 hundredths (be careful – you need to end in the hundredths column.)
4) 125 and 8 thousandths.
5) 23 and 235 thousandths (end in the thousandths column.)
Write each row in order of size starting with the smallest:
1) 2.45m 2.446m 2.35m 2.47m 2.5m
2) 5.21m 5.12m 5.4m 5.123m 5.8m
3) 1.4m 1.45m 1.398m 1.407m 1.3m
4) 0.65m 2.65m 1.65m 6.65m 9.65m
5) 10.62m 10.6m 10.598m 10.48m 10.06m
© H Jackson 2008 / Academic Skills
3