Page 14 - SM inner class 7.cdr

Take LCM of denominators so the LCM of 5 Step I : Ob tain the frac tions.
and 2 10= Step II : Add the nu mer a tors of all frac tions.
Step III : Re tain the com mon de nom i na tor of all
4 (4 ´ 2) 8
[5 ´ 2 = 10] = = frac tions.
5 (5 ´ 2) 10
Step IV : Write the frac tion as Re sult in Step
II ¸ Re sult in Step III.
3 (3 ´ 5) 15 Ex am ple 1 (a). Add the fol low ing frac tions.
[5 ´ 2 = 10] = =
2 (2 ´ 5) 10
1 4
+
8 15 6 6
Now, and are like-fractions.
10 10 So lu tion : We have,
1 4
Converting Mixed Fraction into +
6 6
Improper Fraction
4
3 = (1 + )
To convert a mixed fraction say, 7 into
4 6
improper fraction, follow the steps below: = 5
Step I : Mul ti ply the whole num ber part (i.e. 7) 6
2
by the fraction’s denominator ( . . )i e 4 . So Ex am ple 1 (b). + 3 + 4
7 ´ 4 = 28. 7 7 7
Step II : Add the re sult to the nu mer a tor ( . . )i e 3 So lu tion : We have,
so : 28 + 3 = 31 2 3 4
Step III : Then write the re sult on top of the 7 + 7 + 7
fraction and denominator remains same as (2 + 3 + )
4
be fore ( . . )i e 4 = =
7
31
So, the improper fraction is 9
4 =
7
Converting Improper Fraction into
Subtraction of Like Fractions
Mixed Fraction
31 In order to subtract two like fractions, we
We have an improper fraction say . follow the following steps:
4
Step I : Obtain the two fractions and their
To convert it into mixed fraction, we follow the
steps, below : nu mer a tors.
Step II : Sub tract the smaller nu mer a tor from
Step I : Di vide the nu mer a tor with De nom i na tor
to get the quo tient and re main der. the big ger nu mer a tor.
Step III : Re tain the com mon de nom i na tor.
7 Quotient
Divisor ) 4 31 Step IV : Write the frac tion as Re sult in Step
28 II ¸ Re sult in Step III.
3 Remainder 3 8
Ex am ple: Sub tract from .
Step II : Write the quotient as a whole 10 10
number, then a fraction with remainder as So lu tion : We have to find,
nu mer a tor and di vi sor as de nom i na tor. 8 3
3 - ( Q 8 > 3)
So, mixed fraction is 7 . 10 10
4
(8 - )
3
So, =
Addition of Like Fractions 10
In order to add two or more like fractions, we 5
=
follow these steps : 10

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Mathematics In Focus - 7