Đáp án:
Giải thích các bước giải:
Bài 1 :
a ) $\frac{13}{15}$ + $\frac{4}{7}$ - $\frac{101}{105}$ = $\frac{91}{105}$ + $\frac{60}{105}$ - $\frac{101}{105}$ = $\frac{151}{105}$ - $\frac{101}{105}$ = $\frac{50}{105}$ = $\frac{10}{21}$
b ) $\frac{2}{5}$ + $\frac{3}{5}$ x $\frac{4}{9}$ = $\frac{2}{5}$ + $\frac{4}{15}$ = $\frac{6}{15}$ + $\frac{4}{15}$ = $\frac{10}{15}$ = $\frac{2}{3}$
c ) $\frac{3}{4}$ x $\frac{5}{2}$ x $\frac{7}{6}$ = $\frac{3 × 5 × 7}{4 × 2 × 3 × 2 }$ = $\frac{35}{16}$
d ) $\frac{1}{2}$ : $\frac{1}{4}$ - $\frac{1}{6}$ = $\frac{1}{2}$ x $\frac{4}{1}$ - $\frac{1}{6}$ = 2 - $\frac{1}{6}$ = $\frac{12}{6}$ - $\frac{1}{6}$ = $\frac{11}{6}$
e ) $\frac{2}{3}$ - $\frac{1}{4}$ + $\frac{2}{9}$ = $\frac{24}{36}$ - $\frac{9}{36}$ + $\frac{8}{36}$ = $\frac{15}{36}$ + $\frac{8}{36}$ = $\frac{23}{36}$
g ) $\frac{5}{2}$ + $\frac{1}{3}$ -$\frac{3}{2}$ = $\frac{15}{6}$ + $\frac{2}{6}$ - $\frac{9}{6}$ = $\frac{17}{6}$ - $\frac{9}{6}$ = $\frac{8}{6}$ = $\frac{4}{3}$
Bài 2 :
a ) X + 2$\frac{1}{4}$ = 5$\frac{2}{3}$
X = 5$\frac{2}{3}$ + 2$\frac{1}{4}$
X = 7$\frac{11}{12}$
b ) X - 1$\frac{4}{5}$ = 3$\frac{2}{7}$
X = 3$\frac{2}{7}$ + 1$\frac{4}{5}$
X = 5$\frac{3}{35}$
c ) X x 3$\frac{1}{2}$ = 4$\frac{3}{4}$
X = 4$\frac{3}{4}$ : 3$\frac{1}{2}$
X = $\frac{19}{4 }$ : $\frac{7}{2}$
X = $\frac{19}{4}$ x $\frac{2}{7}$ = $\frac{19}{14}$
d ) X : 2$\frac{2}{3}$ = 4$\frac{1}{3}$
X = 4$\frac{1}{3}$ x 2$\frac{2}{3}$ = $\frac{13}{3}$ x $\frac{8}{3}$ = $\frac{104}{9}$
