Question

/569

а) 3/20×3-3/10÷2

б) 1/18×7+5/6÷3

в) 5/11÷2+21/22÷3

г) 2/25×10-7/10÷2

/570

а) 4/45×9-2/3÷5

б) 3/8÷6+5/32×4

в) 5/12÷10+7/48×3

г) 7/36×4-5/9÷2

Answer 1

№569
a) $frac{3}{20}*3- frac{3}{10}:2= frac{3*3}{20}- frac{3}{10}* frac{1}{2}= frac{9}{20}- frac{3}{20}= frac{9-3}{20}= frac{6}{20}= frac{3}{10}$
б) $frac{1}{18}*7+ frac{5}{6}:3= frac{7}{18}+ frac{5}{6}* frac{1}{3}= frac{7}{18}+ frac{5}{18}= frac{7+5}{18}= frac{12}{18}= frac{2}{3}$
в) $frac{5}{11}:2+ frac{21}{22}:3= frac{5}{11}* frac{1}{2}+ frac{21}{22}* frac{1}{3}= frac{5}{22}+ frac{21}{66}= frac{5*3+21}{66}= frac{36}{66}= frac{6}{11}$
г) $frac{2}{25}*10- frac{7}{10}:2= frac{2*10}{25}- frac{7}{10} * frac{1}{2}= frac{20}{25}- frac{7}{20}= frac{20*4-7*5}{100}= frac{80-35}{100}= frac{45}{100}$$= frac{9}{20}$

№570
а) $frac{4}{45}*9 - frac{2}{3}:5 = frac{4*9}{45}- frac{2}{3}* frac{1}{5}= frac{36}{45}- frac{2}{15}= frac{36-2*3}{45}= frac{30}{45}= frac{2}{3}$
б) $frac{3}{8}:6+ frac{5}{32}*4= frac{3}{8} * frac{1}{6} + frac{5*4}{32}= frac{3}{48} + frac{20}{32}= frac{3*2+20*3}{96}= frac{66}{96}= frac{11}{16}$
в) $frac{5}{12} :10+ frac{7}{48}*3= frac{5}{12} * frac{1}{10} + frac{7*3}{48}= frac{5}{120} + frac{21}{48}= frac{1}{24}+ frac{21}{48}= frac{1*2+21}{48}= frac{23}{48}$
г) $frac{7}{36} *4- frac{5}{9} :2= frac{7*4}{36} - frac{5}{9} * frac{1}{2}= frac{28}{36} - frac{5}{18} = frac{28-5*2}{36}= frac{18}{36}= frac{1}{2}$