Question

79-1510=
18х415=
411х4 712=
1 34:2124=

Answer 1

$\ frac{7}{9} - frac{15}{10} = frac{7*10-15*9}{90} = frac{70-135}{90} = -frac{65}{90} =- frac{13}{18} \ \ frac{18*4}{15} = frac{72}{15}=4,8\ \ frac{4}{11}*4 frac{7}{12} = frac{4}{11} *frac{55}{12} = frac{220}{132} = frac{110}{66}=1 frac{44}{66}= 1frac{22}{33} \ \ 1 frac{3}{4}: frac{21}{24} = frac{7}{4} * frac{24}{21} =2$