CLASS-7
ADDITION OF FRACTION
ADDITION OF FRACTION
Example-1
8 7 11
Find the addition -------- + ------- + --------
15 30 45
8 7 11
-------- + ------- + --------
15 30 45
Step.1) First we will find the LCM of the given
denominator of the given fraction
Now, divide LCM by the denominator of the given fraction respectively
90 ÷ 15 = 6, 90 ÷ 30 = 3, 90 ÷ 45 = 2
Now, multiply obtained quotient with denominator & numerator of respective fraction –
8 7 11
= ------- + ------- + --------
15 30 45
8 8 X 6 48
------- = ----------- = --------
15 15 X 6 90
7 7 X 3 21
-------- = --------- = --------
30 30 X 3 90
11 11 X 2 22
-------- = --------- = -------
45 45 X 2 90
8 7 11 48 21 22
So, ------ + ------ + ------- = ------- + ------- + -------
15 30 45 90 90 90
48 + 21 + 22 91
= ---------------- = --------
90 90
OR
8 7 11
So,------- + ------- + -------- =
15 30 45
8 X (90/15) + 7 X (90/30) + 11 X (90/45)
-------------------------------------------
90
48 + 21 + 22 91
= ----------------- = -------- (Ans.)
90 90
Example-2
10 7 11
Find the addition ------- + ------ + -------
20 30 50
10 7 11
------- + ------ + -------
20 30 50
Step.1) First we will find the LCM of the given denominator of given fraction
Now, divide LCM by the denominator of the given fraction respectively
300 ÷ 20 = 15, 300 ÷ 30 = 10, 300 ÷ 50 = 6
Now, multiply obtained quotient with denominator & numerator of respective fraction –
10 7 11
= -------- + -------- + ---------
20 30 50
10 10 X 15 150
---------- = ---------------- = ----------
20 20 X 15 300
7 7 X 10 70
---------- = ------------ = ----------
30 30 X 10 300
11 11 X 6 66
--------- = ---------- = --------
50 50 X 6 300
10 7 11 150 70 66
So, ------- + ------ + ------- = ------ + ------ + -------
20 30 50 300 300 300
150 + 70 + 66 286
= ------------------ = ---------
300 300
OR
10 7 11
So, ------ + ------ + -------
20 30 50
10 X (300/20)+ 7 X (300/30)+ 11 X (300/50)
= ----------------------------------------------
300
150 + 70 + 66 286
= -------------------- = ----------- (Ans.)
300 300