Q1. Divide:
(i) 142.45 by 10
(ii) 54.25 by 10
(iii) 3.45 by 10
(iv) 0.57 by 10
(v) 0.043 by 10
(vi) 0.004 by 10\begin{array}{l} \text {Sol. (i) } \quad \frac {142.45}{10} = 14.245 \\ \\\text {(ii) } \quad \frac {54.25}{10} = 5.425 \\ \\\text {(iii) } \quad \frac {3.45}{10} = 0.345 \\ \\\text {(iv) } \quad \frac {0.57}{10} = 0.057 \\ \\\text {(v) } \quad \frac {0.043}{10} =0.0043 \\ \\\text {(vi) } \quad \frac {0.004}{10} = 0.0004 \end{array}Q2. Divide:
(i) 459.5 by 100
(ii) 74.3 by 100
(iii) 5.8 by 100
(iv) 0.7 by 100
(v) 0.48 by 100
(vi) 0.03 by 100\begin{array}{l} \text {Sol. (i) } \quad \frac {459.5}{100} = 4.595 \\ \\\text {(ii) } \quad \frac {74.3}{100} = 0.743 \\ \\\text {(iii) } \quad \frac {5.8}{100} = 0.058 \\ \\\text {(iv) } \quad \frac {0.7}{100} = 0.007 \\ \\\text {(v) } \quad \frac {0.48}{100} = 0.0048 \\ \\\text {(vi) } \quad \frac {0.03}{100} = 0.0003 \\ \end{array}Q3. Divide:
(i) } 235.41 by 1000
(ii) 29.5 by 1000
(iii) 3.8 by 1000
(iv) 0.7 by 1000\begin{array}{l} \text {Sol. (i) } \quad \frac {235.41}{1000} = 0.23541 \\\text {(ii) } \quad \frac {29.5}{1000} = 0.0295 \\ \text {(iii) } \quad \frac {3.8}{1000} = 0.0038 \\ \text {(iv) } \quad \frac {0.7}{1000} = 0.0007 \end{array}Q4. Divide:
(i) 0.45 by 9
(ii) 217.44 by 18
(iii) 319.2 by 2.28
(iv) 40.32 by 9.6
(v) 0.765 by 0.9
(vi) 0.768 by 1.6\begin{array}{l} \text {Sol. (i) } \quad \frac {0.45}{9} = \frac {45}{100 \times 9} = \frac {5}{100} = 0.05 \\ \\\text {(ii) } \quad \frac {217.44}{18} = \frac {21744}{100 \times 18} = \frac {1208}{100} = 12.08 \\ \\\text {(iii) } \quad \frac {319.2}{2.28} = \frac {3192 \times 100}{10 \times 228} = 14 \times 10 = 140 \\ \\\text {(iv) } \quad \frac {40.32}{9.6} = \frac {4032 \times 10}{ 100 \times 96} = \frac {42}{10}= 4.2 \\ \\\text {(v) } \quad \frac {0.765}{0.9} = \frac {765 \times 10}{1000 \times 9} = \frac {85}{100} = 0.85 \\ \\\text {(vi) } \quad \frac {0.768}{1.6} = \frac {768 \times 10}{1000 \times 16} = \frac {48}{100} = 0.48 \end{array}Q5. Divide:
(i) 16.64 by 20
(ii) 0.192 by 12
(iii) 163.44 by 24
(iv) 403.2 by 96
(v) 16.344 by 12
(vi) 31.92 by 228\begin{array}{l} \text {Sol. (i) } \quad \frac {16.64}{20} = \frac {1664}{100 \times 20} = \frac {832}{1000} = 0.832 \\ \\\text {(ii) } \quad \frac {0.192}{12} =\frac {192}{1000 \times 12} = \frac {16}{1000} = 0.016 \\ \\\text {(iii) } \quad \frac {163.44}{24} = \frac {16344}{24 \times 100} = \frac {681}{100} = 6.81 \\ \\\text {(iv) } \quad \frac {403.2}{96} = \frac {4032}{96 \times 10} = \frac {42}{10} = 4.2 \\ \\\text {(v) } \quad \frac {16.344}{12} = \frac {16344}{12 \times 1000} = \frac {1362}{1000} = 1.362 \\ \\\text {(vi) } \quad \frac {31.92}{228} = \frac {3192}{228 \times 100} = \frac {14}{100} = 0.14 \end{array}Q6. Divide:
(i) 15.68 by 20
(ii) 164.6 by 200
(iii) 403.80 by 30\begin{array}{l} \text {Sol. (i) } \quad \frac {15.68}{20} = \frac {1568}{20 \times 100} = \frac {784}{1000} = 0.784 \\ \\\text {(ii) } \quad \frac {164.6}{200} = \frac {1646}{200 \times 10} = \frac {823}{1000} = 0.832 \\ \\\text {(iii) } \quad \frac {403.80}{30} = \frac {40380}{30 \times 100} = \frac {13460}{1000} = 13.460 \end{array}Q7. Divide:
(i) 76 by 0.019 \quad (ii) 88 by 0.08
(iii) 148 by 0.074
(iv) 7 by 0.014\begin{array}{l} \text {Sol. (i) } \quad \frac {76}{0.019} = \frac {76 \times 1000}{19} = 4000 \\ \\\text {(ii) } \quad \frac {88}{0.08} = \frac {88 \times 100}{8} = 11 \times 100 = 1100 \\ \\\text {(iii) } \quad \frac {148}{0.074} =\frac {148 \times 1000}{74} = 2 \times 1000 = 2000 \\ \\\text {(iv) } \quad \frac {7}{0.014} = \frac {7 \times 1000}{14} = \frac {1000}{2} = 500 \\ \end{array}Q8. Divide:
(i) 20 by 50
(ii) 8 by 100
(iii) 72 by 576
(iv) 144 by 15\begin{array}{l} \text {Sol. (i) } \quad \frac {20}{50} = \frac {2}{5} = 0.4 \\ \\\text {(ii) } \quad \frac {8}{100} = 0.08 \\ \\\text {(iii) } \quad \frac {72}{576} = \frac {18}{144} = \frac {1}{8} = 0.125 \\ \\\text {(iv) } \quad \frac {144}{15} = \frac {48}{5} = 9.6 \end{array}
(i) 142.45 by 10
(ii) 54.25 by 10
(iii) 3.45 by 10
(iv) 0.57 by 10
(v) 0.043 by 10
(vi) 0.004 by 10\begin{array}{l} \text {Sol. (i) } \quad \frac {142.45}{10} = 14.245 \\ \\\text {(ii) } \quad \frac {54.25}{10} = 5.425 \\ \\\text {(iii) } \quad \frac {3.45}{10} = 0.345 \\ \\\text {(iv) } \quad \frac {0.57}{10} = 0.057 \\ \\\text {(v) } \quad \frac {0.043}{10} =0.0043 \\ \\\text {(vi) } \quad \frac {0.004}{10} = 0.0004 \end{array}Q2. Divide:
(i) 459.5 by 100
(ii) 74.3 by 100
(iii) 5.8 by 100
(iv) 0.7 by 100
(v) 0.48 by 100
(vi) 0.03 by 100\begin{array}{l} \text {Sol. (i) } \quad \frac {459.5}{100} = 4.595 \\ \\\text {(ii) } \quad \frac {74.3}{100} = 0.743 \\ \\\text {(iii) } \quad \frac {5.8}{100} = 0.058 \\ \\\text {(iv) } \quad \frac {0.7}{100} = 0.007 \\ \\\text {(v) } \quad \frac {0.48}{100} = 0.0048 \\ \\\text {(vi) } \quad \frac {0.03}{100} = 0.0003 \\ \end{array}Q3. Divide:
(i) } 235.41 by 1000
(ii) 29.5 by 1000
(iii) 3.8 by 1000
(iv) 0.7 by 1000\begin{array}{l} \text {Sol. (i) } \quad \frac {235.41}{1000} = 0.23541 \\\text {(ii) } \quad \frac {29.5}{1000} = 0.0295 \\ \text {(iii) } \quad \frac {3.8}{1000} = 0.0038 \\ \text {(iv) } \quad \frac {0.7}{1000} = 0.0007 \end{array}Q4. Divide:
(i) 0.45 by 9
(ii) 217.44 by 18
(iii) 319.2 by 2.28
(iv) 40.32 by 9.6
(v) 0.765 by 0.9
(vi) 0.768 by 1.6\begin{array}{l} \text {Sol. (i) } \quad \frac {0.45}{9} = \frac {45}{100 \times 9} = \frac {5}{100} = 0.05 \\ \\\text {(ii) } \quad \frac {217.44}{18} = \frac {21744}{100 \times 18} = \frac {1208}{100} = 12.08 \\ \\\text {(iii) } \quad \frac {319.2}{2.28} = \frac {3192 \times 100}{10 \times 228} = 14 \times 10 = 140 \\ \\\text {(iv) } \quad \frac {40.32}{9.6} = \frac {4032 \times 10}{ 100 \times 96} = \frac {42}{10}= 4.2 \\ \\\text {(v) } \quad \frac {0.765}{0.9} = \frac {765 \times 10}{1000 \times 9} = \frac {85}{100} = 0.85 \\ \\\text {(vi) } \quad \frac {0.768}{1.6} = \frac {768 \times 10}{1000 \times 16} = \frac {48}{100} = 0.48 \end{array}Q5. Divide:
(i) 16.64 by 20
(ii) 0.192 by 12
(iii) 163.44 by 24
(iv) 403.2 by 96
(v) 16.344 by 12
(vi) 31.92 by 228\begin{array}{l} \text {Sol. (i) } \quad \frac {16.64}{20} = \frac {1664}{100 \times 20} = \frac {832}{1000} = 0.832 \\ \\\text {(ii) } \quad \frac {0.192}{12} =\frac {192}{1000 \times 12} = \frac {16}{1000} = 0.016 \\ \\\text {(iii) } \quad \frac {163.44}{24} = \frac {16344}{24 \times 100} = \frac {681}{100} = 6.81 \\ \\\text {(iv) } \quad \frac {403.2}{96} = \frac {4032}{96 \times 10} = \frac {42}{10} = 4.2 \\ \\\text {(v) } \quad \frac {16.344}{12} = \frac {16344}{12 \times 1000} = \frac {1362}{1000} = 1.362 \\ \\\text {(vi) } \quad \frac {31.92}{228} = \frac {3192}{228 \times 100} = \frac {14}{100} = 0.14 \end{array}Q6. Divide:
(i) 15.68 by 20
(ii) 164.6 by 200
(iii) 403.80 by 30\begin{array}{l} \text {Sol. (i) } \quad \frac {15.68}{20} = \frac {1568}{20 \times 100} = \frac {784}{1000} = 0.784 \\ \\\text {(ii) } \quad \frac {164.6}{200} = \frac {1646}{200 \times 10} = \frac {823}{1000} = 0.832 \\ \\\text {(iii) } \quad \frac {403.80}{30} = \frac {40380}{30 \times 100} = \frac {13460}{1000} = 13.460 \end{array}Q7. Divide:
(i) 76 by 0.019 \quad (ii) 88 by 0.08
(iii) 148 by 0.074
(iv) 7 by 0.014\begin{array}{l} \text {Sol. (i) } \quad \frac {76}{0.019} = \frac {76 \times 1000}{19} = 4000 \\ \\\text {(ii) } \quad \frac {88}{0.08} = \frac {88 \times 100}{8} = 11 \times 100 = 1100 \\ \\\text {(iii) } \quad \frac {148}{0.074} =\frac {148 \times 1000}{74} = 2 \times 1000 = 2000 \\ \\\text {(iv) } \quad \frac {7}{0.014} = \frac {7 \times 1000}{14} = \frac {1000}{2} = 500 \\ \end{array}Q8. Divide:
(i) 20 by 50
(ii) 8 by 100
(iii) 72 by 576
(iv) 144 by 15\begin{array}{l} \text {Sol. (i) } \quad \frac {20}{50} = \frac {2}{5} = 0.4 \\ \\\text {(ii) } \quad \frac {8}{100} = 0.08 \\ \\\text {(iii) } \quad \frac {72}{576} = \frac {18}{144} = \frac {1}{8} = 0.125 \\ \\\text {(iv) } \quad \frac {144}{15} = \frac {48}{5} = 9.6 \end{array}