12 meters = ? feet 
$$12 * 3.281 = 3.372  feet$$ 
2 miles = ? kilometers 
$$2 * 1.609 = 3.218  kilometers$$  
2 pound = ? kilograms 
$$2 * 0.454 = 0.908  kilograms$$
 77 Fahrenheit = ? Celsius 
$$( 77 - 32 ) * \frac{5}{9} = 25  C$$ 
77 Celsius = ? Fahrenheit 
$$( 77 * \frac{9}{5}) + 32 = 170.6  F$$ 
0 Fahrenheit = ? Celsius 
$$(0 - 32 ) * \frac{5}{9} = 17.7  C$$ 
0 Celsius = ? Fahrenheit 
$$( 0 * \frac{9}{5}) + 32 = 32  F$$