Thực hiện phép tính (tính nhanh nếu có thể) (a) A = 26 , 3 − 7 , 63 + 13 , 7 + 200 , 4 − 12 , 37 .

a) \(A = 26,3 - 7,63 + 13,7 + 200,4 - 12,37\).

\[A = \left( {26,3 + 13,7} \right) + \left( { - 7,63 - 12,37} \right) + 200,4\]

\[A = 40 + \left( { - 20} \right) + 200,4\]

\[A = 20 + 200,4\]

\[A = 220,4\].

b) \(B = \frac{{13}}{5}.\frac{{ - 3}}{7} + 2,6.\frac{{ - 4}}{7} + 2\frac{2}{5}\).

\(B = \frac{{13}}{5}.\frac{{ - 3}}{7} + \frac{{13}}{5}.\frac{{ - 4}}{7} + 2\frac{2}{5}\)

\(B = \frac{{13}}{5}.\left( {\frac{{ - 3}}{7} + \frac{{ - 4}}{7}} \right) + 2\frac{2}{5}\)

\(B = \frac{{13}}{5}.\left( { - 1} \right) + \frac{{12}}{5}\)

\(B = \frac{{ - 13}}{5} + \frac{{12}}{5}\)

\(B = \frac{{ - 1}}{5}\).

c) \(C = \left( { - 9} \right).3 + 3.{\left( { - 2} \right)^3} - 49\).

\(C = - 27 + \left( { - 24} \right) - 49\)

\(C = - 100\).