Question

[Hoàng Ngân Hà]

Các bạn ơi giúp mik với!

Answer 1

[ILoveMath]

\(a,\dfrac{2}{5}+\dfrac{9}{15}=\dfrac{2}{5}+\dfrac{3}{5}=\dfrac{5}{5}=1\\ b,\dfrac{15}{45}+\dfrac{25}{30}=\dfrac{1}{3}+\dfrac{5}{6}=\dfrac{2}{6}+\dfrac{5}{6}=\dfrac{7}{6}\\ c,\dfrac{1}{6}+\dfrac{8}{24}=\dfrac{1}{6}+\dfrac{1}{3}=\dfrac{1}{6}+\dfrac{2}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)

Answer 2

[Lú Toán, Mù Anh]

A) \(\dfrac{2}{5}\) + \(\dfrac{9}{15}\)          B) \(\dfrac{15}{45}\)  +  \(\dfrac{25}{30}\)         C) \(\dfrac{1}{6}\) + \(\dfrac{8}{24}\)

= \(\dfrac{2}{5}\) + \(\dfrac{3}{5}\)                 = \(\dfrac{1}{3}\) + \(\dfrac{5}{6}\)                = \(\dfrac{1}{6}\) + \(\dfrac{1}{3}\)

= \(\dfrac{5}{5}\) = 1                  = \(\dfrac{2}{6}\) + \(\dfrac{5}{6}\)                = \(\dfrac{1}{6}\) + \(\dfrac{2}{6}\)

                               = \(\dfrac{7}{6}\)                       = \(\dfrac{3}{6}\) = \(\dfrac{1}{2}\)