Tính bằng cách thuận tiện (236 x 66 - 236 x 16)/(118 x 37 + 118 x 63)

a) \[\frac{{236 \times 66 - 236 \times 16}}{{118 \times 37 + 118 \times 63}}\]

= \[\frac{{236 \times \left( {66 - 16} \right)}}{{118 \times \left( {37 + 63} \right)}}\]

= \[\frac{{236 \times 50}}{{118 \times 100}}\]

= $\frac{\cancel{118}\times \cancel{2}\times \cancel{50}}{\cancel{118}\times \cancel{50}\times \cancel{2}}$

= 1

b) \[\frac{5}{{12}} \times \frac{{13}}{6} - \frac{5}{{12}} \times \frac{7}{6} + \frac{5}{{12}}\]

= \[\frac{5}{{12}} \times \left( {\frac{{13}}{6} - \frac{7}{6} + 1} \right)\]

= \[\frac{5}{{12}} \times 2\]

= \[\frac{5}{6}\]