Question

câu 1: không đổi ra phân số hãy thực hiện phép tính : a)\(6^5_8-4^1_2\) b)- 2,013 + 1,01 câu 2:tìm x biết : \(\dfrac{2}{3}x+\dfrac{1}{2}=\dfrac{1}{10}\)

Answer 1

Câu 1:

a)\(6\dfrac{5}{8}-4\dfrac{1}{2}=\left(6+\dfrac{5}{8}\right)-\left(4+\dfrac{1}{2}\right)\\ =6+\dfrac{5}{8}-4-\dfrac{1}{2}\\ =\left(6-4\right)+\left(\dfrac{5}{8}-\dfrac{1}{2}\right)\\ =2+\dfrac{1}{8}\\ =2\dfrac{1}{8}\)

b) \(-2.013+1.01=-1.003\)

Câu 2:

\(\dfrac{2}{3}x+\dfrac{1}{2}=\dfrac{1}{10}\\ \dfrac{2}{3}x=\dfrac{1}{10}-\dfrac{1}{2}\\ \dfrac{2}{3}x=-\dfrac{2}{5}\\ x=-\dfrac{2}{5}:\dfrac{2}{3}\\ x=-\dfrac{2}{5}.\dfrac{3}{2}\\ x=-\dfrac{3}{5}\\ x=-0.6\)

Vậy x=-0.6