12.
a)
[tex](1 \frac{4}{5} \div \frac{3}{7} ) \div 1 \frac{2}{5} = ( \frac{9}{5} \times \frac{7}{3} ) \div \frac{7}{5} = ( \frac{3}{5} \times \frac{7}{1} ) \times \frac{5}{7} = \frac{21}{5} \times \frac{5}{7} = \frac{3}{1} \times \frac{1}{1} = 3[/tex]
b)
[tex]3 \frac{3}{4} \div (2 \frac{1}{6} - 1 \frac{1}{2} ) = \frac{15}{4} \div ( 2 \frac{1}{6} - 1 \frac{3}{6} ) = \frac{15}{4} \div (1 \frac{7}{6} - 1 \frac{3}{6} ) = \frac{15}{4} \div \frac{4}{6} = \frac{15}{4} \times \frac{6}{4} = \frac{15}{2} \times \frac{3}{4} = \frac{45}{8} = 5 \frac{5}{8} [/tex]
13.
a)
[tex] \frac{4}{7} \div 3 = \frac{4}{7} \times \frac{1}{3} = \frac{4}{21} [/tex]
b)
[tex] \frac{9}{10} \div 6 = \frac{9}{10} \times \frac{1}{6} = \frac{9}{60} = \frac{3}{20} [/tex]
c)
[tex]1 \frac{1}{7} \div 8 = \frac{8}{7} \times \frac{1}{8} = \frac{1}{7} \times 1 = \frac{1}{7} [/tex]
d)
[tex]2 \frac{2}{5} \div 4 = \frac{12}{5} \times \frac{1}{4} = \frac{3}{5} \times \frac{1}{1} = \frac{3}{5} [/tex]
