NCERT Solution class 7 Mathematics EXERCISE- 2.2
CHAPTER – 2
EXERCISE – 2.2
Q1. Which of the drawings (a) to (d) show:
(i) 2 x 1/5
SOLUTION:-
2 X (1/5) Represents the addition of 2 figures each represents 1 shaded part out of given 5 equal parts .
2 x (1/5) is represented by figure(d).
(ii) 2 x 1/2
SOLUTION:-
2 x 1/2 represents the addition of 2 figures each represents 1 shaded parts out of given 2 equal parts.
2 x 1/2 is represented by fig (b).
(iii) 3 x 2/3
SOLUTION:-
3 X (2/3) represents the addition of 3 figures each represents 2 shaded parts out of the given 3 equal parts
3 x (2/3) is represented by fig (a).
Q3. Multiply and reduce to lowest form and convert into a mixed fraction:-
(i) 7 x 3/5
SOLUTION:-
By the rule of multiplication of fraction
Product of fraction = ( product of numerator) /( product of denominator)
Then,
= (7/1) x (3/5)
= ( 7 x 3 ) / (1 x5 )
= (21/5)
= 4.2
(ii) 4 x (1/3)
SOLUTION:-
By the rule multiplication of faction,
Product of fraction= ( product of numerator)/ ( product of denominator)
Then,
= (4/1) x (1/3)
= (4 x 1 ) / (1 x 3 )
= (4/3)
= 1.3
(iii) 2 x (6/7)
SOLUTION:-
= 12/7
= 1.7
(iv) 5 x (2/9)
SOLUTION:-
= (10/9)
= 1.1
(v) (2/3) x 4
SOLUTION:-
= (8/3)
= 2.6
(vi) (5/2) x 6
SOLUTION:-
= (30/2)
= 15
(vii) 11 x 4/7
SOLUTION:-
= (44/7)
= 6.2
(viii) 20 x 4/5
SOLUTION:-
= 80/5
= 16
(ix) 13 x (1/3)
SOLUTION:-
= (13/3)
= 4.3
(x) 15 x (3/5)
SOLUTION:-
= (45/ 5)
= 9
Q4. Shade
(a) ½ of the circles in box (a)
(b) 2/3 of the triangles in box (b)
(c) 3/5 of the squares in the box (c)
SOLUTION:-
(i) From the question,
We may observe that there are 12 circles in the given box. So, we have to shade ½ of the circles in the box.
= 12 x ½ = 12/2
= 6
So we have to shade any 6 circles in the box.
(ii) From the question,
We may observes that there are 9 triangles in the given box. so, we have to shade 2/3 of the triangles in the box.
= 9 x (2/3)
= 18/3
= 6
(iii) From the question,
We may observes that there are 15 squares in the given box. So, we have to shade 3/5 of the squares in the box.
= 15 x(3/5)
= 45/5
= 9
Q5. Find:
(a) ½ of (i) 24 (ii) 46
SOLUTION:-
(i) 24
We have,
= ½ x 24
= 24/2
=12
(ii) 46
We have,
= ½ x 46
= 46/2
= 23
(b) 2/3 of (i) 18 (ii) 27
SOLUTION:-
(i) 18
We have,
= 2/3 x 18
= 2 x 6
= 12
(ii) 27
We have,
= 2/3 x 27
= 2 x 9
= 18
(c) ¾ of (i) 16 (ii) 36
SOLUTION:-
(i) 16
We have,
= ¾ x 16
= 3 x 4
= 12
(ii) 36
We have,
= ¾ x 36
= 3 x 9
= 27
(d) 4/5 of (i) 20 (ii) 35
SOLUTION:-
(i) 20
We have,
= 4/5 x 20
= 4 x 4
= 16
(ii) 35
We have,
= 4/5 x 35
= 4 x 7
= 28
Q6. Multiply the express as a mixed fraction:
(a) 3 x 26/5
SOLUTION:-
= 78/5
(B) 5 X 27/4
SOLUTION:-
= 135/4
(C) 7 X 9/4
SOLUTION:-
= 63/4
(D) 4 X 19/3
SOLUTION:-
= 76/3
(E) 13/4 X 6
SOLUTION:-
= 78/4
(F) 17/5 X 8
SOLUTION:-
= 136/5
Q7. Find:
(a) ½ of (i) 11/4 (ii) 38/9
SOLUTION:-
By the rule of multiplication of fraction,
Product of fraction = (product of numerator) / ( product of denominator)
Then,
= ½ x (11/4)
= (1×11) / (2 x 4)
= (11/8)
(ii) By the rule of multiplication of fraction
Product of fraction = (product of numerator)/(products of denominator)
Then,
= ½ x (38/9)
= (1 x 38) / (2x 9)
= (38/18)
= 19/9
(b) 5/8 of (i) 23/6 (ii) 29/3
SOLUTION:-
(i) By the rule multiplication of fraction,
Product of fraction = ( product of numerator) / ( product of denominator)
Then,
= (5/8) x (23/6)
= (5 x 23) /(8 x 6)
= (115/48)
(ii) By the rule of multiplication of fraction,
Product of fraction = (product of numerator ) / (product of denominator)
Then,
= (5/8) x (29/3)
= (5 x 29) / (8×3)
= (145/24)
Q8. Vidya and pratap went for a picnic . their mother gave then a water bottle that contained 5 liters of water . vidya consumed 2/5 of the water . pratap consumed the remainning the water .
(i) How much water did vidya drink ?
(ii) What fraction of the total quantity of water did pratap drink ?
SOLUTION:-
(i) From the question , it is given that ,
Amount of water in the water bottle = 5 liters
Amount of water consumed by vidya = 2/5 of 5 liters
= (2/5) x5
= 2 liters
So the total amount of water drank by vidya is 2 liters
(ii) From the question it is given that
Amount of water in the water bottle = 5 litres
Then ,
Amount of water consumed by pratap = (1-water consumed by vidya)
= ( 1 – (2/5))
= (5 – 2) /5
= 3/5
Total amount of water consumed by pratap = 3/5 of 5 liters
= (3/5) x 5
= 3 liters