Exercise 2.4
Q 1, Ex 2.4 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Find :
(i) 12 \div \dfrac{3}{4}
Sol :
12 \div \dfrac{3}{4} =12\times \dfrac{4}{3} = 16
(ii) 4\div \dfrac{5}{6}
Sol :
14 \div\dfrac{5}{6} 14\times \dfrac{6}{5} =\dfrac{84}{5}
(iii) 8\div \dfrac{7}{3}
Sol :
8\div \dfrac{7}{3} =8\times \dfrac{3}{7} =\dfrac{24}{7}
(iv) 4\div \dfrac{8}{3}
Sol :
4\div \dfrac{8}{3} =4\times \dfrac{3}{8} =\dfrac{3}{2}
(v) 3\div 2\dfrac{1}{3}
Sol :
3\div 2\dfrac{1}{3} =3\div \dfrac{7}{3} =3\times\dfrac{3}{7} \dfrac{9}{7}
(vi) 5\div 3\dfrac{4}{7}
Sol :
5\div 3\dfrac{4}{7} =5\div \dfrac{25}{7} =5\times \dfrac{7}{25} =\dfrac{7}{5}
Q 2, Ex 2.4 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Question 2
Find the reciprocal of each of the following fractions. Classify the reciprocals as proper fractions, improper fractions and whole numbers.
(i) \dfrac{3}{7} (ii) \dfrac{5}{8} (iii) \dfrac{9}{7}
(iv) \dfrac{6}{5} (v) \dfrac{12}{7} (vi) \dfrac{1}{8}
(vii) \dfrac{1}{11}
Sol :
Note : A proper fraction is the fraction which has its denominator greater than its numerator while improper fraction is the fraction which has its numerator greater than its denominator. Whole numbers are a collection of all positive integers including 0.
(i) \dfrac{3}{7}
Reciprocal =\dfrac{7}{3}
Therefore, it is an improper fraction.
(ii) \dfrac{5}{8}
Reciprocal =\dfrac{8}{5}
Therefore, it is an improper fraction.
(iii) \dfrac{9}{7}
Reciprocal =\dfrac{7}{9}
Therefore, it is an proper fraction.
(iv) \dfrac{6}{5}
Reciprocal =\dfrac{5}{6}
Therefore, it is an proper fraction.
(v) \dfrac{12}{7}
Reciprocal =\dfrac{7}{12}
Therefore, it is an proper fraction.
(vi) \dfrac{1}{8}
Reciprocal =\dfrac{8}{1}
Therefore, it is a whole number.
(vii) \dfrac{1}{11}
Reciprocal =\dfrac{11}{1}
Therefore, it is a whole number.
Q 3, Ex 2.4 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Question 3
Find :
(i) \dfrac{7}{3} \div 2 (ii) \dfrac{4}{9} \div 5 (iii) \dfrac{6}{13} \div 7 (iv) 4\dfrac{1}{3} \div 3 (v) 3\dfrac{1}{2} \div 4 (vi) 4\dfrac{3}{7} \div 7
Sol :
(i) \dfrac{7}{3} \div 2 =\dfrac{7}{3} \times \dfrac{1}{2} =\dfrac{7}{6}
(ii) \dfrac{4}{9} \div 5 =\dfrac{4}{9} \times \dfrac{1}{5} =\dfrac{4}{45}
(iii) \dfrac{6}{13} \div 7 =\dfrac{6}{13} \times \dfrac{1}{7} =\dfrac{6}{91}
(iv) 4\dfrac{1}{3} \div 3 =\dfrac{13}{3} \div \dfrac{3}{1} =\dfrac{13}{3} \times \dfrac{1}{3} =\dfrac{13}{9}
(v) 3\dfrac{1}{2} \div 4 =\dfrac{7}{2} \div \dfrac{4}{1} =\dfrac{7}{2} \times \dfrac{1}{4} =\dfrac{7}{8}
(vi) 4\dfrac{3}{7} \div 7 =\dfrac{31}{7} \div \dfrac{1}{7} =\dfrac{31}{7} \times \dfrac{1}{7} =\dfrac{31}{49}
Q 4, Ex 2.4 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Find :
(i) \dfrac{2}{5} \div \dfrac{1}{2} (ii) \dfrac{4}{9} \div \dfrac{2}{3}
(iii) \dfrac{3}{7} \div \dfrac{8}{7} (iv) 2\dfrac{1}{3} \div \dfrac{3}{5}
(v) 3\dfrac{1}{2} \div \dfrac{8}{3} (vi) \dfrac{2}{5} \div 1\dfrac{1}{2}
(vii) 3\dfrac{1}{5} \div 1\dfrac{2}{3} (viii) 2\dfrac{1}{5} \div 1\dfrac{1}{5}
Sol :
(i) \dfrac{2}{5} \div \dfrac{1}{2} =\dfrac{2}{5} \times \dfrac{2}{1} =\dfrac{4}{5}
(ii) \dfrac{4}{9} \div \dfrac{2}{3} =\dfrac{4}{9} \times \dfrac{3}{2} =\dfrac{2}{3}
(iii) \dfrac{3}{7} \div \dfrac{8}{7} =\dfrac{3}{7} \times \dfrac{7}{8} =\dfrac{3}{8}
(iv) 2\dfrac{1}{3} \div \dfrac{3}{5} =\dfrac{7}{3} \div \dfrac{3}{5} =\dfrac{7}{3} \times \dfrac{5}{3} =\dfrac{35}{9}
(v) 3\dfrac{1}{2} \div \dfrac{8}{3} =\dfrac{7}{2} \div \dfrac{8}{3} =\dfrac{7}{2} \times \dfrac{3}{8} =\dfrac{21}{16}
(vi) \dfrac{2}{5} \div 1\dfrac{1}{2} =\dfrac{2}{5} \div \dfrac{3}{2} =\dfrac{2}{5} \times \dfrac{2}{3} =\dfrac{4}{15}
(vii) 3\dfrac{1}{5} \div 1\dfrac{2}{3} =\dfrac{16}{5} \div \dfrac{5}{3} =\dfrac{16}{5} \times \dfrac{3}{5} =\dfrac{48}{25}
(viii) 2\dfrac{1}{5} \div 1\dfrac{1}{5} =\dfrac{11}{5} \div \dfrac{6}{5} =\dfrac{11}{5} \times \dfrac{5}{6} =\dfrac{11}{6}
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