Question

a, 20%.\(\dfrac{15}{36}\) - (\(\dfrac{2}{5}+\dfrac{2}{3})\) : \(1\dfrac{1}{5}\)

b, \(\dfrac{6}{7}+\dfrac{5}{4}-\dfrac{4}{7}-\dfrac{-25}{4}\)

Help me... Đây là đề cương toán 6 các bạn giúp mik nha nhớ nêu cách làm

Answer 1

a,

= \(\dfrac{20}{100}.\dfrac{15}{36}-\)(\(\dfrac{2}{5}+\dfrac{2}{3}\)):\(\dfrac{6}{5}\)

= \(\dfrac{20.15}{100.36}\)- ( \(\dfrac{6}{15}+\dfrac{10}{15}\)): \(\dfrac{6}{5}\)

= \(\dfrac{1.5}{5.12}-\dfrac{16}{15}:\dfrac{6}{5}\)

= \(\dfrac{1.1}{1.12}-\dfrac{16.5}{10.6}\)

= \(\dfrac{1}{12}-\dfrac{16.1}{2.6}\)

= \(\dfrac{1}{12}\) - \(\dfrac{16}{12}\)

= \(\dfrac{1}{12}+\dfrac{\left(-16\right)}{12}\)

= \(\dfrac{15}{12}\) = \(\dfrac{5}{4}\)

b,

= \(\dfrac{6}{7}+\dfrac{5}{4}+\dfrac{\left(-4\right)}{7}+\dfrac{25}{4}\)

= (\(\dfrac{6}{7}+\dfrac{\left(-4\right)}{7}\)) + (\(\dfrac{5}{4}+\dfrac{25}{4}\))

= \(\dfrac{2}{7}+\dfrac{30}{4}\)

= \(\dfrac{2}{7}+\dfrac{15}{2}\)

= \(\dfrac{4}{14}+\dfrac{105}{14}\)

= \(\dfrac{109}{14}\)