Question

Выполните действия: 3/28 + 15/28-11/28; 3) 1- 17/20; 3 7/23-1 4/23 + 5 9/23; 4) 5 3/8-3 5/8 .

Answer 1

$\displaystyle 1) \frac{3}{28} +\frac{15}{28} -\frac{11}{28} = \frac{3+15-11}{28} =\frac{7}{28} =\frac{7:7}{28:7} =\frac{1}{4}$

$\displaystyle 2) 3\frac{7}{23} -1\frac{4}{23} +5\frac{9}{23} = (3-1+5)+\frac{7-4+9}{23} =7+\frac{12}{23} =7\frac{12}{23}$

$\displaystyle 3) 1 -\frac{17}{20} =\frac{20}{20}-\frac{17}{20} =\frac{20-17}{20}=\frac{3}{20}$

$\displaystyle 4) 5\frac{3}{8} -3\frac{5}{8}= (5-3)+\frac{3-5}{8} =2-\frac{2}{8}=2-\frac{2:2}{8:2}=\\\\=2-\frac{1}{4}=1+\frac{4}{4}-\frac{1}{4}=1+\frac{4-1}{4}=1\frac{3}{4}$