1. Tính (theo mẫu):
a) $\frac{3}{5}$ + $\frac{1}{4}$ = $\frac{12 + 5}{20}$ = $\frac{17}{20}$
b) $\frac{2}{3}$ + $\frac{4}{5}$ = ...............
c) $\frac{7}{10}$ - $\frac{2}{5}$ = ................
d) $\frac{11}{9}$ - $\frac{6}{7}$ = ................
e) 5 + $\frac{1}{3}$ = ...............
g) $\frac{7}{2}$ - 2 = ...............
2. Tính rồi rút gọn (theo mẫu):
a) $\frac{6}{5}$ x $\frac{1}{3}$ = $\frac{\not{6}^{2}\times 1}{5 \times \not{3}^{1}}$ = $\frac{2}{5}$
b) $\frac{15}{9}$ x $\frac{3}{25}$ = .........
c) $\frac{9}{7}$ x $\frac{2}{9}$ = ........
d) $\frac{2}{5}$ : $\frac{2}{3}$ = ..........
e) $\frac{1}{9}$ : $\frac{7}{3}$ = .........
g) 5 : $\frac{5}{7}$ = .........
3. Tính:
a) $\frac{5}{9}$ + ($\frac{2}{3}$ - $\frac{1}{2}$) = ..........
b) $\frac{4}{7}$ + $\frac{2}{7}$ x $\frac{1}{6}$ = ........
c) $\frac{8}{11}$ - $\frac{5}{11}$ : $\frac{5}{4}$ = ..........
4. Nêu bài toán theo tóm tắt rồi giải:
Bài toán:
................................................................
................................................................
Bài giải:
.............................................................
.............................................................
.............................................................