Tính: a)1/2+52/4=;b) 56/5:4

* Hướng dẫn giải

$\begin{array}{l}a)\frac{1}{2}+\frac{52}{4}=\frac{2}{4}+\frac{52}{4}=\frac{54}{4}=\frac{27}{2}\\ b)\frac{56}{5}:4=\frac{56}{5}\times \frac{1}{4}=\frac{14\times 1}{5\times 1}=\frac{14}{5}\\ c)\frac{12}{56}+\frac{7}{8}=\frac{12}{56}+\frac{49}{56}=\frac{61}{56}\\ d)\frac{25}{12}\times \frac{4}{5}=\frac{5\times 1}{3\times 1}=\frac{5}{3}\end{array}$