Question

12. Найдите значение выражения. a)(8-2/5)×1 1/4. b)(3 1/3-1/9)×3. c)(9-3/4)×1 1/3. d)(2 1/5-1/15)×15.

Answer 1

$(8-\frac{2}{5} )*1\frac{1}{4} =(\frac{40}{5} -\frac{2}{5} )*\frac{5}{4} =\frac{38}{5} *\frac{5}{4} =\frac{19}{2} =9.5\\\\(3\frac{1}{3} -\frac{1}{9} )*3=(\frac{10}{3} -\frac{1}{9} )*\frac{3}{1} =(\frac{30}{9} -\frac{1}{9} )*\frac{3}{1} =\frac{29}{9} *\frac{3}{1} =\frac{29}{3} =9\frac{2}{3} \\\\(9-\frac{3}{4} )*1\frac{1}{3} =(\frac{36}{4} -\frac{3}{4} )*\frac{4}{3} =\frac{33}{4} *\frac{4}{3} =11$

$(2\frac{1}{5} -\frac{1}{15} )*15=(\frac{11}{5} -\frac{1}{15} )*\frac{15}{1} =(\frac{33}{15} -\frac{1}{15} )*\frac{15}{1} =\frac{32}{15} *\frac{15}{1} =32$