Question

Tính nhanh :

a. 53.39 + 47.39 - 53.21 - 47.21

b. ( 252 + 2. 28 - 5.28 ) : 28 

Answer 1

a) \(53.39+47.39-53.21-47.21\)

\(=39\left(53+47\right)-21\left(53+47\right)\)

\(=39.100-21.100\)

\(=3900-2100=1800\)

b) \(\left(252+2.28-5.28\right):28\)

\(=\left(9.28+2.28-5.28\right):28\)

\(=28\left(9+2-5\right):28\)

\(=28.6:28\)

\(=6\)