Use of Equal Sign

1
Use of Equal Sign
2
Approximate Sign vs Equal Sign
When do we use or in our number
statements?
3
Which is correct?
?
1 678 is not the same as 1 680.
1 678 1 680
or
?
1 678 1 680
1 680 is an approximate value of 1 678.
Therefore must be used.
4
Which is correct?
6 345 m? is an exact value of 6 ? 345 m?.
Therefore must be used.
?
6 ? 345 m? 6 345 m?
or
?
6 ? 345 m? 6 345 m?
6 345 m? is not an approximate value of 6 ? 345
m?.
5
Using unitary method to solve word
problems E.g. 40 1 600 10 1 600 4
400 100 10 x 400
4 000 40 1600 100 4 000
?
?
?
?
?
?
?
This is because amount of money is not the same
as .
6
Ali and Shawn have a total of 210 stamps. Shawn
has twice as many stamps as Alan. How many
stamps does Shawn have? 3 units 210 1
unit 210 3 70 2
units 2 x 70
140 Shawn has 140 stamps.

?
?
?
?
?
7
Dollar and cent notation Muthu bought a pen for
40 and a book for 1.40. How much did he spend
altogether? Amount spent altogether 1.40
40 1.40
?
?
8
Dollar and cent notation Muthu bought a pen
for 40 and a book for 1.40. How much did she
spend altogether? Amount spent altogether
1.40 40 1.80
?
9
Conversion of unit of measurements
during intermediate steps E.g. 52 litres
52 000 cm3 52 litres 52 000 52 litres 52
000
?
?
Units missing
?
10
A fraction is not equal or the same as a whole
number!
?
?
1 8 x 16 128
Note The answer may be correct but the method
is wrong and therefore no mark will be awarded.
11
BUT
?
Here the fraction represents a whole number.
?
1 8 x 16 128
Or we can also use the unitary method
?
1 unit 16 8 units 8 x 16
128
?
John had 128 stamps at first.
?
12
Percentage
Many pupils will do this
?
Why?

75

• This is incorrect because
• is missing!
• is not the same as itself x 100 !

13
SO
?

75
Or we can also use the unitary method
?
4 units 100 3 unit
75
?