FRACTIONS,
DECIMALS, APPROXIMATIONS
AND PERCENTAGES
In this post am going to talk
about what the topic is, above. I shouldnt have told you because you have seen
what the essence of this post is about as above. The explanation is going to be
brief and straight to the point based on JAMB syllabus. These are what we are
going to treat about it:
|
a) Fractions and
Decimlas
b) Significant
Figures
c) Decimal places
d) Percentage errors
|
Candidates Should be able to:
i.
Perform basic operations (
 ) in fractions and decimals;
ii. Express to
specifiednumber of significant figures and decimal places
|
|
e) Simple interests
f) Profit and Loss
percent
g) Ratio, proportion
and Rate
|
iii. Calculate simple
interest, profit and loss percent,ratio proportion and rate.
|
FRACTIONS
Make sure you do the drills below.
Note: If
you miss up to five questions I advice you to visit your Juniour Mathematics
text. Because it’s very important you get it all. Comment with your answers
before I give mine, enjoy the rest of the
lecture.
DRILLS
1.
Find 
of 6.5m in cm.
of 6.5m in cm.
2.
Find 
of 2
hours in seconds.
of 2 hours in seconds.
3.
Find 
of 4.5 m in millimeters.
of 4.5 m in millimeters.
Find the number
of minutes in the following.
4.
hour.
hour.
5.
of 2 hours.
of 2 hours.
6.
of 10 hours.
of 10 hours.
Find
the number of cm in the following.
7. of 2 metres.
of 2 metres.
8. 
of 8 kilometres.
of 8 kilometres.
In each of
the following, express the first quantity as a fraction of the second.
9. 10
min, 1 h.
h.
10. $50, $550.
11. 7 weeks, 3 months.
Find the value of the following
12. 
of 5.4 cm.
of 5.4 cm.
13. 
of 3 weeks.
of 3 weeks.
14. 
of 3.41 metres.
of 3.41 metres.
15. 
of 2h 24min.
of 2h 24min.
Lets get into fraction proper, what do you think
fraction may mean? Well let me not leave you wondering what it is, since we are
not here for the definition, simply stated fraction is part of a whole.
TYPES OF
FRACTION
Well I dont know if there are other forms of
fraction but I am going to treat the three I think are common.
·
Vulgar
Fraction :This is a type of fraction expressed in the form a/b
where a and b are integers. Vulgar fraction could be proper fraction:where
a<b or improper fraction where a>b.It is also called raw fraction.
·
Mixed
Fraction: Consist of whole part and proper fractional part.It is
of the form A
where A=whole
part and 
is the proper fractional part e.g 7
is a mixed
fraction.
where A=whole
part and is the proper fractional part e.g 7is a mixed
fraction.
·
Decimal
Fraction:this is expressed in the form A.ab(A=whole part, decimal
point and ab are the decimal fractional part) e.g 7.63 is a decimal fraction.
Addition,
Substraction, Multiplication and Division of Fraction
I intend to
treat Addition, Substraction, Multiplication and Division of Fractions in this
regard. If you find the later diifficult please indicate so that I will treat
everything on it.
Lets do some
problems to get to understand the topic better to get to know that you have a
knowledge of the topic already.
EXAMPLES
1.
which
fraction is greater, 
or 
?
or ?
The common denominator (LCM) of and is 65
and is 65
(i.e. 5 
13)
13) 
Since 
, is the greater fraction.
, is the greater fraction.
To save time I prefer to complete everything
with my non scientific calculator then compare both values. Whichever style you
choose, make sure you make the question Bow before you.
2.
Solve this
as a mini drill, (1
1
) 
5
1) 5
Hint:
Take Note of your BODMAS. It’s very important.
ANS:
3.
of a class of 40 students study history and study study Geography. Every student
studies at least one of these subjects.
of a class of 40 students study history and study study Geography. Every student
studies at least one of these subjects.
How many students study both subjects?
What fraction of the class studies history but
not Geography?
SOLUTION
a.
Number of students studying History
40
24
Number of
students studying Geography
40 30
Total number of
students studying history and geography 24 
54
24 54
Since there are only 40 students in the
class, number studying both
54 
40 14
b. Among
the 24 students studying history, 14 is also studying Geography.
Hence, number of students studying
History only 24 14
24 14 10
Fraction studying history only 
Or
Since of the class study Geography, then of the class study history but not geography.
of the class study Geography, then of the class study history but not geography.
You
have to take a break for a moment, you have some drills coming up. If you have
any problem with what I have done so far, please I will be at your service.
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