Question

fillups in the blankso (12/5×-4/7) × 3/2= ×4/7×3/2​

Answer 1

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Solve:

(i) 2 – 3/5 (ii) 4 + 7/8 (iii) 3/5 + 2/7 (iv) 9/11 – 4/15 (v) 7/10 + 2/5 + 3/2

(vi) 2 + 3 (vii) 8 - 3

Answer:

(i) 2 – 3/5 = 2/1 – 3/5

= (2 * 5 – 3 * 1)/5 [LCM (1, 5) = 5]

= (10 - 3)/5

= 7/5

= 1

(ii) 4 + 7/8 = 4/1 + 7/8

= (4 * 8 + 7)/8 [LCM (1, 8) = 8]

= (32 + 7)/8

= 39/8

= 4

(iii) 3/5 + 2/7 = (3 * 7 + 2 * 5)/35 [LCM (7, 5) = 35]

= (21 + 10)/35

= 31/35

(iv) 9/11 – 4/15 = (9 * 15 – 4 * 11)/165 [LCM (11, 15) = 165]

= (135 - 44)/165

= 91/165

(v) 7/10 + 2/5 + 3/2 = (7 * 1 + 2 * 2 + 3 * 5)/10

= (7 + 4 + 15)/10

= 26/10 [26 and 10 are divided by 2]

= 13/5

= 2

(vi) 2 + 3 = 8/3 + 7/2

= (8 * 2 + 7 * 3)/6 [LCM (2, 3) = 6]

= (16 + 21)/6

= 37/6

= 6

(vii) 8 - 3 = 17/2 – 29/8

= (17 * 4 – 29 * 1)/8 [LCM (2, 8) = 8]

= (68 - 19)/8

= 39/8

= 4

Question 2:

Arrange the following in descending order:

(i) 2/9, 2/3, 8/21 (ii) 1/5, 3/7, 7/10

Answer:

(i) 2/9, 2/3, 8/21 = (2 * 7, 2 * 21, 8 * 3)/63 [LCM (9, 3, 21) = 63]

= (14, 42, 24)/63

= 14/63, 42/63, 24/63

Now, 42/63, 24/63, 14/63 [Arrange in descending order]

So, 2/3, 8/21, 2/9

(ii) 1/5, 3/7, 7/10 = (1 * 14, 3 * 10, 7 * 7)/70

= (14, 30, 49)/70

= 14/70, 30/70, 49/70

Now, 49/70, 30/70, 14/70 [Arrange in descending order]

So, 7/10, 3/7, 1/5

Answer 2

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AnswEr

Solve:

(i) 2 – 3/5 (ii) 4 + 7/8 (iii) 3/5 + 2/7 (iv) 9/11 – 4/15 (v) 7/10 + 2/5 + 3/2

(vi) 2 + 3 (vii) 8 - 3

Answer:

(i) 2 – 3/5 = 2/1 – 3/5

= (2 * 5 – 3 * 1)/5 [LCM (1, 5) = 5]

= (10 - 3)/5

= 7/5

= 1

(ii) 4 + 7/8 = 4/1 + 7/8

= (4 * 8 + 7)/8 [LCM (1, 8) = 8]

= (32 + 7)/8

= 39/8

= 4

(iii) 3/5 + 2/7 = (3 * 7 + 2 * 5)/35 [LCM (7, 5) = 35]

= (21 + 10)/35

= 31/35

(iv) 9/11 – 4/15 = (9 * 15 – 4 * 11)/165 [LCM (11, 15) = 165]

= (135 - 44)/165

= 91/165

(v) 7/10 + 2/5 + 3/2 = (7 * 1 + 2 * 2 + 3 * 5)/10

= (7 + 4 + 15)/10

= 26/10 [26 and 10 are divided by 2]

= 13/5

= 2

(vi) 2 + 3 = 8/3 + 7/2

= (8 * 2 + 7 * 3)/6 [LCM (2, 3) = 6]

= (16 + 21)/6

= 37/6

= 6

(vii) 8 - 3 = 17/2 – 29/8

= (17 * 4 – 29 * 1)/8 [LCM (2, 8) = 8]

= (68 - 19)/8

= 39/8

= 4

Question 2:

Arrange the following in descending order:

(i) 2/9, 2/3, 8/21 (ii) 1/5, 3/7, 7/10

Answer:

(i) 2/9, 2/3, 8/21 = (2 * 7, 2 * 21, 8 * 3)/63 [LCM (9, 3, 21) = 63]

= (14, 42, 24)/63

= 14/63, 42/63, 24/63

Now, 42/63, 24/63, 14/63 [Arrange in descending order]

So, 2/3, 8/21, 2/9

(ii) 1/5, 3/7, 7/10 = (1 * 14, 3 * 10, 7 * 7)/70

= (14, 30, 49)/70

= 14/70, 30/70, 49/70

Now, 49/70, 30/70, 14/70 [Arrange in descending order]

So, 7/10, 3/7, 1/5