12. Determine a. (1)/(5)+1 d. 2-(3)/(2) g. (2)/(3)+(1)/(2) b. 1-(1)/(5) e. (3)/(4)+5 h. (2)/(3)-(1)/(2) c. 2+(3)/(2) f. 5-(3)/(4)

Vamos resolver cada uma das expressões:<br /><br />a. $\frac {1}{5}+1 = \frac {1}{5} + \frac {5}{5} = \frac {6}{5}$<br /><br />d. $2-\frac {3}{2} = \frac {4}{2} - \frac {3}{2} = \frac {1}{2}$<br /><br />g. $\frac {2}{3}+\frac {1}{2} = \frac {4}{6} + \frac {3}{6} = \frac {7}{6}$<br /><br />b. $1-\frac {1}{5} = \frac {5}{5} - \frac {1}{5} = \frac {4}{5}$<br /><br />e. $\frac {3}{4}+5 = \frac {3}{4} + \frac {20}{4} = \frac {23}{4}$<br /><br />h. $\frac {2}{3}-\frac {1}{2} = \frac {4}{6} - \frac {3}{6} = \frac {1}{6}$<br /><br />c. $2+\frac {3}{2} = \frac {4}{2} + \frac {3}{2} = \frac {7}{2}$<br /><br />f. $5-\frac {3}{4} = \frac {20}{4} - \frac {3}{4} = \frac {17}{4}$<br /><br />Portanto, as respostas corretas são:<br /><br />a. $\frac {6}{5}$<br />d. $\frac {1}{2}$<br />g. $\frac {7}{6}$<br />b. $\frac {4}{5}$<br />e. $\frac {23}{4}$<br />h. $\frac {1}{6}$<br />c. $\frac {7}{2}$<br />f. $\frac {17}{4}$