Question

[bùi thị kim anh]

2. Tính:
A) 3/7 x 7/9 x 1/2.
B) 5/8 x 4 x 1/2.
C) 4 x 1/24 x 3.

Answer 1

[Nguyễn Ngọc Thiện Nhân]

\(\dfrac{3}{7}\times\dfrac{7}{9}\times\dfrac{1}{2}\)

\(=\dfrac{3\times7\times1}{7\times9\times2}\)

\(=\dfrac{21}{126}\)

\(=\dfrac{1}{6}\)

\(\dfrac{5}{8}\times4\times\dfrac{1}{2}\\ =\dfrac{5}{8}\times\dfrac{4}{1}\times\dfrac{1}{2}\\ =\dfrac{5\times4\times1}{8\times1\times2}\\ =\dfrac{20}{16}\\ =\dfrac{5}{4}\)

\(4\times\dfrac{1}{24}\times3\\ =\dfrac{4}{1}\times\dfrac{1}{24}\times\dfrac{3}{1}\\ =\dfrac{4\times1\times3}{1\times24\times1}\\ =\dfrac{12}{24}\\ =\dfrac{1}{2}\)