SUBTRACTING FRACTIONS MADE EASY - LUCID EXPLANATION OF FRACTION PROBLEMS
Please study
Fractions before Subtracting Fractions
if you have not already done so.
There we studied about
half, quarter, three fourth
with examples and exercises.
Learn/Teach
Fractions through Fun Games.
For details, see near
the bottom of this page.
Also study
Fractions Made Easy.
There we studied about
concept of fraction in general
with examples and exercises.
We also introduced Like and Unlike
Fractions which are used here.
The knowledge of
Equivalent Fractions,
Conversion of Improper to Mixed and Mixed to Improper Fractions
and
Least Common Multiple (L.C.M.)
is also used here.
Here, we explain subtraction of fractions
with like and unlike denominators
in a lucid way.
We include solved examples and
problems for practice with answers.
Subtracting of Like Fractions
Difference of like fractions
= (Difference of their numerators)⁄(Common denominator)
Examples :
(i) 5⁄7 - 4⁄7 = (5 - 4)⁄7 = 1⁄7
(ii) 9⁄11 - 2⁄11 - 4⁄11 - 1⁄11
= (9 - 2 - 4 - 1)⁄11 = 2⁄11
Subtracting of Unlike Fractions
Method of Subtracting Unlike Fractions
Step 1 :
Find the
L.C.M.
of denominators of given fractions.
Step 2 :
Convert the given fractions into
equivalent like fractions
with their L.C.M. as common denominator.
Step 3 :
Subtract the like fractions so obtained.
Step 4 :
Reduce the fraction obtained in step 3 to its
lowest terms
and convert it into
mixed fraction
if required.
Solved Example 1 of Subtracting Fractions
Find the difference 13⁄18 - 7⁄12
Solution :
Let us find the L.C.M. of the denominators.
6| 18 12
----------------
3 2
L.C.M. = 6 x 3 x 2 = 36.
13⁄18 - 7⁄12
= (13 x 2)⁄(18 x 2) - (7 x 3)⁄(12 x 3)
= 26⁄36 - 21⁄36 = (26 - 21)⁄36
= 5⁄36. Ans.
Solved Example 2 of Subtracting Fractions
Simplify 8⁄9 - 5⁄12 - 13⁄27 + 5⁄6
Solution :
Let us find the L.C.M.. of the denominators.
3| 9 12 27 6
-------------------------------
3| 3 4 9 2
-------------------------------
2| 1 4 3 2
-------------------------------
1 2 3 1
L.C.M. = 3 x 3 x 2 x 2 x 3 = 108.
8⁄9 - 5⁄12 - 13⁄27 + 5⁄6
Now 108 is taken as the common denominator.
The number with which we have to multiply each
denominator to get 108 is taken and that number
multiplies each numerator as shown below.
= ( 8 x 12 - 5 x 9 - 13 x 4 + 5 x 18)⁄108
= (96 - 45 - 52 + 90)⁄108 = 89⁄108.
Ans.
Solved Example 3 of Subtracting Fractions
Find the value of
6 4⁄5 -
3 4⁄15 +
4 3⁄10 .
Solution :
6 4⁄5 -
3 4⁄15 +
4 3⁄10 . .
= (6 x 5 + 4)⁄5 - (3 x 15 + 4)⁄15 + (4 x 10 + 3)⁄10
= 34⁄5 - 49⁄15 + 43⁄10
Let us find the L.C.M.. of the denominators.
5| 5 15 10
-----------------------
1 3 2
L.C.M. = 5 x 3 x 2 = 30.
The required value = 34⁄5 - 49⁄15 + 43⁄10
= (34 x 6 - 49 x 2 + 43 x 3)⁄30
= (204 - 98 + 129)⁄30 = 235⁄30
= 23547⁄306
= 47⁄6
= 7 5⁄6 . Ans.
Word Problems on Subtracting Fractions
For Application of various topics of Fractions
including Subtracting Fractions to Word Problems
go to
Fraction Word problems.
Learning/Teaching Math Can Be Fun
Here is a collection of kids math
games and fun math activities for
the class room or for the home, to
make math exciting and easy to learn.
They help you
* To save you time and money to be
spent on resources, games and books.
* To become a wonderful, fun teacher
or parent who knows how to make math
fun, interesting and effective.
* To cater for all different ability
levels and cater for different
learning styles.
* To see your kids math skills soar
and their grades in math going
up and up.
This Collection of Fun Math Games
are electronic books (e-books)
that are downloaded to your computer
in a flash. You can start printing
games right away. You get to print
only what you want and as many
copies as you need.
For more information or to have
some FREE samples or to order
click
HERE.
Exercise on Subtracting Fractions
Find the values of
- 9⁄13 - 4⁄13
- 16⁄17 - 9⁄17 - 3⁄17 - 1⁄17
- 13⁄63 - 7⁄42
- 4⁄21 - 9⁄14 - 11⁄35 + 49⁄30
- 5 3⁄4 -
4 5⁄16 +
6 7⁄12
For Answers, see at the bottom of the page.
Answers to Exercise on Subtracting Fractions
- 5⁄13
- 3⁄17
- 5⁄126
- 91⁄105
- 8 1⁄48


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