Đề học kì 1 Toán 7 năm 2025 – 2026 xã Đông Anh – Hà Nội

a) $\dfrac{- 3}{4} + \dfrac{2}{3}:\dfrac{4}{5}$

$= \dfrac{- 3}{4} + \dfrac{5}{6}$

$= \dfrac{- 9}{12} + \dfrac{10}{12}$

$= \dfrac{1}{12}$

b) $\dfrac{5}{11} \cdot \dfrac{7}{9} + \dfrac{5}{11} \cdot \dfrac{2}{9} + \dfrac{- 5}{11}$

$\begin{array}{l}={\displaystyle \frac{5}{11}}\cdot \left({\displaystyle \frac{\text{7}}{\text{9}}}+{\displaystyle \frac{2}{9}}-1\right)\\ ={\displaystyle \frac{5}{11}}\cdot \left(1-1\right)=0\end{array}$$\begin{array}{l} {= \dfrac{5}{11} \cdot \left( {\dfrac{\text{7}}{\text{9}} + \dfrac{2}{9} - 1} \right)} \\ {= \dfrac{5}{11} \cdot \left( {1 - 1} \right) = 0} \end{array}$

c) $\dfrac{11}{25} - \dfrac{5}{13} - \dfrac{- 7}{17} - \dfrac{8}{13} + \dfrac{10}{17}$

$\begin{array}{l}={\displaystyle \frac{11}{25}}-\left({\displaystyle \frac{5}{13}}+{\displaystyle \frac{8}{13}}\right)+\left({\displaystyle \frac{7}{17}}+{\displaystyle \frac{10}{17}}\right)\\ ={\displaystyle \frac{11}{25}}-1+1={\displaystyle \frac{11}{25}}\end{array}$$\begin{array}{l} {= \dfrac{11}{25} - \left( {\dfrac{5}{13} + \dfrac{8}{13}} \right) + \left( {\dfrac{7}{17} + \dfrac{10}{17}} \right)} \\ {= \dfrac{11}{25} - 1 + 1 = \dfrac{11}{25}} \end{array}$

d) $\sqrt{\dfrac{4}{25}} + \left| {- 0,75} \right| - \dfrac{9}{5} \cdot \left( \dfrac{- 1}{3} \right)^{2} + \dfrac{13}{4}$

$\begin{array}{l}={\displaystyle \frac{2}{5}}+0,75-{\displaystyle \frac{9}{5}}\cdot {\displaystyle \frac{1}{9}}+{\displaystyle \frac{13}{4}}\\ ={\displaystyle \frac{2}{5}}+{\displaystyle \frac{3}{4}}-{\displaystyle \frac{1}{5}}+{\displaystyle \frac{13}{4}}\\ =\left({\displaystyle \frac{2}{5}}-{\displaystyle \frac{1}{5}}\right)+\left({\displaystyle \frac{3}{4}}+{\displaystyle \frac{13}{4}}\right)\\ ={\displaystyle \frac{1}{5}}+{\displaystyle \frac{7}{2}}={\displaystyle \frac{37}{10}}\end{array}$$\begin{array}{l} {= \dfrac{2}{5} + 0,75 - \dfrac{9}{5} \cdot \dfrac{1}{9} + \dfrac{13}{4}} \\ {= \dfrac{2}{5} + \dfrac{3}{4} - \dfrac{1}{5} + \dfrac{13}{4}} \\ {= \left( {\dfrac{2}{5} - \dfrac{1}{5}} \right) + \left( {\dfrac{3}{4} + \dfrac{13}{4}} \right)} \\ {= \dfrac{1}{5} + \dfrac{7}{2} = \dfrac{37}{10}} \end{array}$