Question

Bài 2b,54 x 47 - 47 x 53 - 20 - 27          Bài 2c, 10000 - 47 x 72 - 47 x 28

Answer 1

\(2b,\)\(54\times47-47\times53-20-27.\)

\(=47\times54-47\times53-47\)

\(=47\times\left(54-53-1\right)\)

\(=47\times0=0\)

\(2c,\)\(10000-47\times72-47\times28\)

\(=100\times100-47\times\left(72+28\right)\)

\(=100\times100-47\times100\)

\(=100\times\left(100-47\right)\)

\(=100\times53=5300\)

Answer 2

2b

54 x 47 - 47 x 53 - 20 - 27 = 47 x ( 54 - 53 ) - 20 - 27 = 47 - 20 - 27 = 47 - ( 20 + 27 ) = 47 - 47 = 0

2c

10000 - 47 x 72 - 47 x 28 = 10000 - 47 x ( 72 - 28 ) = 10000 - 47 x 44 = 10000 - 2068 = 7932