Đáp án:
Bài 1: $a) \dfrac{133}{12}$
$b) \dfrac{49}{15}$
$c) \dfrac{5}{7}$
$d) 12$
Bài 2: $a) \dfrac{31}{4}$
$b) \dfrac{13}{12}$
Giải thích các bước giải:
Bài 1:
$a) 11\dfrac{3}{4}-\left ( 6\dfrac{5}{6}-4\dfrac{1}{2} \right )+1\dfrac{2}{3}\\=\dfrac{47}{4}-\left ( \dfrac{41}{6}-\dfrac{9}{2} \right )+\dfrac{5}{3}\\=\dfrac{47}{4}-\dfrac{7}{3}+\dfrac{5}{3}\\=\dfrac{133}{12}\\b) 2\dfrac{17}{20}-1\dfrac{11}{15}+6\dfrac{9}{20}:3\\=\dfrac{57}{20}-\dfrac{26}{15}+\dfrac{129}{20}.\dfrac{1}{3}\\=\dfrac{57}{20}-\dfrac{26}{15}+\dfrac{43}{20}\\=\dfrac{49}{15}\\c) 4\dfrac{3}{7}:\left ( \dfrac{7}{5}.4\dfrac{3}{7} \right )\\=\dfrac{31}{7}:\left ( \dfrac{7}{5}.\dfrac{31}{7} \right )\\=\dfrac{31}{7}:\left ( \dfrac{1}{5}.31 \right )\\=\dfrac{31}{7}:\dfrac{31}{5}\\=\dfrac{31}{7}.\dfrac{5}{31}\\=\dfrac{1}{7}.5=\dfrac{5}{7}\\d) \left ( 3\dfrac{2}{9}.\dfrac{15}{23}.1\dfrac{7}{29} \right ):\dfrac{5}{23}\\=\left ( \dfrac{29}{9}.\dfrac{15}{23}.\dfrac{36}{29} \right ).\dfrac{23}{5}\\=\left ( \dfrac{15}{23}.4 \right ).\dfrac{23}{5}\\=\dfrac{60}{23}.\dfrac{23}{5}=12$
Bài 2:
$a) 11\dfrac{3}{4}-\left ( 6\dfrac{5}{6}-4\dfrac{1}{2}+1\dfrac{2}{3} \right )\\=\dfrac{47}{4}-\left ( \dfrac{41}{6}-\dfrac{9}{2}+\dfrac{5}{3} \right )\\=\dfrac{47}{4}-4=\dfrac{31}{4}\\b) \left ( 5\dfrac{7}{8}-2\dfrac{1}{4}-0,5 \right ):2\dfrac{23}{26}\\=\left ( \dfrac{47}{8}-\dfrac{9}{4}-\dfrac{1}{2} \right ):\dfrac{75}{26}\\=\dfrac{25}{8}.\dfrac{26}{75}\\=\dfrac{1}{4}.\dfrac{13}{3}=\dfrac{13}{12}$
