ORDERING AND COMPARING DECIMALS
Comparing Decimals
Example
Which number is
bigger: 0.43 or 0.403?
Looking at the
digits, 403 seems bigger than 43. But, it is not!
Method
Step1: Draw the
place_Value_tables and put the numbers
th
|
h
|
o
|
.
|
t
|
h
|
th
|
0
|
.
|
4
|
3
|
|||
0
|
.
|
4
|
0
|
2
|
Step2: Put 0 into the
empty square
th
|
h
|
o
|
.
|
t
|
h
|
th
|
0
|
.
|
4
|
3
|
0
|
||
0
|
.
|
4
|
0
|
2
|
= 3 bigger
Step3: Compare the
first column on the left. If the digits are equal, move to next number until
the bigger number
0.43 is bigger than 0.402
Example
Which number is
smaller: 8.003 or 8.01?
Method
Step1: Draw the placeValuetable
and put the numbers
th
|
h
|
o
|
.
|
t
|
h
|
th
|
8
|
.
|
0
|
0
|
3
|
||
8
|
.
|
0
|
1
|
Step2: Put 0 into the
empty square
th
|
h
|
o
|
.
|
t
|
h
|
th
|
8
|
.
|
0
|
0
|
3
|
||
8
|
.
|
0
|
1
|
0
|
= =
0 is smaller
Step3: Compare the
first column on the left. If the digits are equal, move to next number until
the required smaller number.
8.003 is smaller than 8.01
Ordering Decimals
Ascending order is
arranging the numbers from the Smallest to the Biggest numbers
Ascending order: 1.01, 2.01, 3.01, 4.01
Descending order
is arranging the numbers from the Biggest to the Smallest numbers.
5.2, 4,2 ,
3.2, 1.2
Descending -> Down => from big
to small
Example
Put the 1.517,
1.57, 1.08 and 0.8 in ascending order
Method
Step1: Draw the placeValueTable and put the numbers
th
|
h
|
o
|
.
|
t
|
h
|
th
|
1
|
.
|
5
|
1
|
7
|
||
1
|
.
|
5
|
7
|
|||
1
|
.
|
0
|
8
|
|||
0
|
.
|
8
|
Step2: Put 0 into the empty square
th
|
h
|
o
|
.
|
t
|
h
|
th
|
|
1
|
.
|
5
|
0
|
7
|
3
|
||
1
|
.
|
5
|
7
|
0
|
4
|
||
1
|
.
|
0
|
8
|
0
|
2
|
||
0
|
.
|
8
|
0
|
0
|
1
|
(1) (2) (3) (4) number
Step3: Compare the first column on the left. If
the digits are equal, move to next number until the required smallest number
(for Ascending), write number
0.8 , 1.08, 1.517, 1.57
Example
Put the 0.402,
1.2, 0.41, 0.375 in descending order.
Method
Step1: Draw the placeValueTable and put the numbers
th
|
h
|
o
|
.
|
t
|
h
|
th
|
0
|
.
|
4
|
0
|
2
|
||
1
|
.
|
2
|
||||
0
|
.
|
4
|
1
|
|||
0
|
.
|
3
|
7
|
5
|
Step2: Put 0 into the empty square
th
|
h
|
o
|
.
|
t
|
h
|
th
|
|
0
|
.
|
4
|
3
|
2
|
3
|
||
1
|
.
|
2
|
0
|
0
|
4
|
||
0
|
.
|
4
|
1
|
0
|
2
|
||
0
|
.
|
3
|
7
|
5
|
1
|
Step3: Compare the first column on the left. If
the digits are equal, move to next number until the required biggest number
(for descending), write number
1.2,
1.432, 0.410, 0.375
Using Number Line
Example
What are the values
A, B and C?
Method(count blank spaces)
Step1: Find the
interval value between 2 known number (1.0 and 1.5).
Count number of blanks: 5 blanks / ‘spaces’ between 1.0 and 1.5
Each marker = 1.5 -1.0 / 5 = 0.5/5 = 0.1
=>
1.0 + 0.1 = 1.1 for first marker
Step2: Put in the
marker
1.0 + 0.1=1.1, 1.1+0.1 = 1.2, …
Step3: Answer
A = 1.2 , B = 1.8 and C = 2.4
Example
What are the
values of A and B?
Method (marker + 1)
Step1: Find the
interval value between 2 known number (1.0 and 2.0).
- Count number of marker I between
the 2 numbers, and ADD 1
- 4 marker + 1 = 5
Each marker = 2.0 -2.0 / 5 = 1.0/5 = 0.2
=> 1.0 + 0.2 = 1.2 for first marker
Step2: Put in the
marker
1.0 + 0.2, 1.2+0.2, …
Step3: Answer
A = 1.6, B = 1.2
~~ the end ~~~ :)
