$\frac{5.6 +5.7}{ 5.8 +20} = \frac{5.(6 +7)}{5.8 +4.5} = \frac{5.13}{5.(8 +4)} = \frac{13}{12}$
$\frac{8.9-4.15}{12.7-180} = \frac{2.4.3.3-4.3.5}{12.7-12.15} = \frac{12.6-12.5}{12.(17 -15)} = \frac{12.(6 -5)}{12.2} = \frac{12}{12.2} = \frac{1}{2}$
$Ta$ $có:$ $MC$ $= 12$
$⇒ \frac{1}{2} = \frac{1.6}{2.6} = \frac{6}{12}; \frac{13}{12}$