Question

tính

3/4+1/4x2/5-1/2

Answer 1

\(\dfrac{3}{4}+\dfrac{1}{4}\times\dfrac{2}{5}-\dfrac{1}{2}\\ =\dfrac{3}{4}+\dfrac{1}{10}-\dfrac{1}{2}\\ =\dfrac{15}{20}+\dfrac{2}{20}-\dfrac{10}{20}\\ =\dfrac{15-10+2}{2}\\ =\dfrac{7}{2}\)