Add Following Fractions 1 3 4 And 3 8

Add the following fractions : (i) 1.3/4 and 3/8 (ii) 2/5, 2.3/15 and 7/10 (iii) 1.7/8, 1.1/2 and 1. … 18 and 3. 5/6 (vi) 3.1/8, 5….

Answers:

(i) 1.34 and 3/8

= 7/4 + 3/8

= (7 × 2)/(4 × 2) + 3/8 (L.C.M. of 4,8  = 8)

= (14/8) + (3/8) = (14 + 3)/8 = 17/8 = 2.1/8

(ii) 2/5 , 2.3/15 and 7/10

= (2/5) + (33/15) + (7/10)

= (2 × 6)/(5 × 6) + (33 × 2)/(15 × 2) + (7 × 3)/(10 × 3)

(L.C.M. of 5, 15 and 10 = 30)

= (12/30) + (66/30) + (21/30)

= (12/30) + (66/30) + (21/30)

= (121 + 66 + 21)/30 = 99/30 = (99 ÷ 3)/(30 ÷ 3)

= 33/10 = 3.3/10

(iii) 1.7/8, 1.1/2 and 1.3/4

= 1 × 8 + 7/8 + (1 × 2 + 1)/2 + (1 × 4 + 3)/4

= (15/8) + (3/2) + (7/4) = (15 × 1)/(8  × 1)  + (3 × 4)/(2  × 4)

+ (7 × 2)/(4  × 2)

= (15/8) + (12/8) + (14/8) = (15 + 12 + 14)/8

(L.C.M. 8, 2, and 4 is 8)

= 41/8 = 5.1/8

(iv) (3.3/4) + (2.1/6) + (1.5/8)

= (3 × 4 + 3)/4 + (2 × 6 + 1)/6 + (1 × 8 + 5)/8

= (15/4) + (13/6) + (13/8) (L.C.M. 4, 6 and 8 is 24)

= (15 × 6)/(4× 6) + (13 × 4)/(6 × 4) + (13 × 3)/(8 × 3)

= (90/24) + (52/24) + (39/24) = 181/24 = 7.13/24

(v) 2.8/9 , 11/18 and 3. 5/6

= (26/9) + (11/18) + (23/6) = (26 × 2)/(9 × 2) + 11/18 + (23 × 3)/(6 × 3)

(L.C.M. of 9, 18 and 6 = 18)

= (52/18) + (11/18) + ( 69/18)

= (52 + 11 + 69)/18 = 132/18 = (132 ÷ 6)/(18 ÷ 6)

= 22/3 = 7.1/3

(vi) (3.1/8) + (5.5/12) + (5/16)

= (3 × 8 + 1)/8 + (5 × 12 + 5)/12 + 5/16

= (25/8) + (65/12) + (5/16)

(L.C.M. 8, 12 and 16 is 48)

= (25 × 6)/(8 × 6) + (65 × 4)/(12 × 4) + (5 × 3)/(16 × 3)

= (150/48) + (260/48) + (15/48)

= (150 + 260 + 15)/48

= 425/48 = 8.41/48