Bài 1:
1$\frac{2}{3}$ + 1$\frac{3}{5}$
= $\frac{5}{3}$ + $\frac{8}{5}$
= $\frac{25}{15}$ + $\frac{24}{15}$
= $\frac{25 + 24}{15}$
= $\frac{49}{25}$
3$\frac{5}{9}$ - 2$\frac{7}{9}$
= $\frac{32}{9}$ - $\frac{25}{9}$
= $\frac{32-25}{9}$
= $\frac{7}{9}$
3$\frac{1}{3}$ + 2$\frac{1}{2}$
= $\frac{10}{3}$ + $\frac{5}{2}$
= $\frac{20}{6}$ + $\frac{15}{6}$
= $\frac{20+15}{6}$
= $\frac{35}{6}$
3$\frac{2}{5}$ - 1$\frac{1}{10}$
= $\frac{17}{5}$ - $\frac{11}{10}$
= $\frac{34}{10}$ - $\frac{11}{10}$
= $\frac{34-11}{10}$
= $\frac{23}{10}$
Bài 3:
a) X x $\frac{1}{2}$ = $\frac{1}{3}$
X = $\frac{1}{3}$ : $\frac{1}{2}$
X = $\frac{1}{3}$ x $\frac{2}{1}$
X = $\frac{2}{3}$
b) x : $\frac{4}{5}$ = $\frac{5}{2}$
x = $\frac{5}{2}$ x $\frac{4}{5}$
x = 2
c) $\frac{2}{9}$ : x = $\frac{2}{3}$
x = $\frac{2}{9}$ : $\frac{2}{3}$
x = $\frac{2}{9}$ x $\frac{3}{2}$
x = $\frac{1}{3}$
d) X x $\frac{1}{7}$ = $\frac{4}{9}$ + $\frac{2}{7}$
X x $\frac{1}{7}$ = $\frac{46}{63}$
X = $\frac{46}{63}$ : $\frac{1}{7}$
X = $\frac{46}{9}$
