$$\frac{7+5}{3}=\frac{12}{3}=\frac{4}{1}=4$$

$$\frac{7+5}{3+3}=\ \frac{12}{6}=\frac{2}{1}=2$$

$$\frac{9+1-7}{4+4+4}=\ \frac{3}{12}=\frac{1}{4}$$

$$\frac{9+1-7}{4}=\frac{3}{4}$$

Devemos somar e ou subtrair os numeradores e denominadores.

Devemos encontrar um denominador comum (frações equivalentes) e somar e/ou subtrair os numeradores.

Devemos copiar os denominadores e somar e/ou subtrair os numeradores.

Devemos copiar os numeradores e somar e/ou subtrair os denominadores.

$$\frac{3+7}{2+4}=\frac{10}{6}=\frac{5}{3}$$

$$\frac{3+7}{4}=\frac{10}{4}=\frac{5}{2}$$

$$\frac{6}{4}+\frac{7}{4}=\frac{13}{4}$$

$$\frac{16}{6\ }-\frac{15}{6}=\frac{16-15}{6}=\frac{1}{6}$$

$$\frac{8}{6}-\frac{5}{6}=\frac{8-5}{6}=\ \frac{3}{6}=\frac{1}{2}$$

$$\frac{8-5}{3-1}=\ \frac{3}{1}=3$$

$$\frac{7\ .\ 4}{3}=\frac{28}{3}$$

$$\frac{7\ .\ 4}{2\ .\ 3}=\frac{28}{6}=\frac{14}{3}$$

$$\frac{7\ .\ 4}{2}=\frac{28}{2}=\frac{14}{1}=14$$

$$\frac{9\ .\ 8}{9}=\frac{72}{9}\ =\ \frac{24}{3}=\ 8$$

$$\frac{9\ .\ 8}{4}\ =\ \frac{72}{4}\ =\ \frac{36}{2}\ =\ 18$$

$$\frac{9\ .\ 8}{4\ .\ 9}\ =\frac{72}{36}\ =\ \frac{8}{4}\ =\ 2\$$

$$\frac{2\ .\ 5}{7}=\frac{10}{7}$$

$$\frac{2\ .\ 5}{7\ .\ 7}=\frac{10}{49}$$

4 = $$\frac{4}{1}$$

4 = $$\frac{4}{4}$$

$$\frac{7}{7}\ .\ \frac{2}{5}\ =\ \frac{7\ .\ 2}{7\ .\ 5}\ =\ \frac{14}{35}$$

$$\frac{7}{1}\ .\ \frac{2}{5}\ =\ \frac{7\ .\ 2}{1\ .\ 5}=\frac{14}{5}$$

$$\frac{8}{1}\ .\ \frac{2}{3}=\ \frac{8\ .\ 2}{1\ .\ 3}=\ \frac{16}{3}$$

$$\frac{8}{8}\ .\ \frac{2}{3}=\ \frac{8\ .\ 2}{8\ .\ 3}=\ \frac{16}{24}\ =\ \frac{2}{3}$$

$$\frac{4}{4}\ .\ \frac{5}{9}\ =\ \frac{4\ .\ 5\ }{4\ .\ 9}=\ \frac{20}{36}=\ \frac{5}{9}$$

$$\frac{4}{1}.\ \frac{5}{9}\ =\ \frac{4\ .\ 5}{1\ .\ 9}\ =\ \frac{20}{9}$$

$$\frac{7}{9}$$

$$\frac{9}{7}$$

$$\frac{7}{12}$$

$$\frac{12}{7}$$

$$\frac{3}{4}$$

$$\frac{4}{3}$$