Question

tính bằng hai cách a)(5,28 + 4,72) x 4,5 b) (7,8 -2,3 )x6,4

Answer 1

a: C1: \(\left(5,28+4,72\right)\cdot4,5\)

\(=10\cdot4,5\)

=45

C2: \(\left(5,28+4,72\right)\cdot4,5\)

\(=5,28\cdot4,5+4,72\cdot4,5\)

\(=23,76+21,24\)

=45

b: C1: \(\left(7,8-2,3\right)\cdot6,4\)

\(=5,5\cdot6,4\)

=35,2

C2: \(\left(7,8-2,3\right)\cdot6,4\)

\(=7,8\cdot6,4-2,3\cdot6,4\)

\(=49,92-14,72\)

=35,2