Đề kiểm tra giữa kì 2 Toán 6 có đáp án (Mới nhất) (Đề 3)

a) $\frac{15}{34}+\frac{7}{21}+\frac{19}{34}-\frac{20}{15}+\frac{3}{7}$ 

$=\left(\frac{15}{34}+\frac{19}{34}\right)+\left(\frac{7}{21}-\frac{20}{15}\right)+\frac{3}{7}$ 

$=\frac{15+19}{34}+\left(\frac{7:7}{21:7}-\frac{20:5}{15:5}\right)+\frac{3}{7}$ 

$=\frac{34}{34}+\left(\frac{1}{3}-\frac{4}{3}\right)+\frac{3}{7}$ 

$=1+\frac{-3}{3}+\frac{3}{7}=1+(-1)+\frac{3}{7}=\frac{3}{7}$ 

b) $26\frac{1}{5}.\frac{3}{4}-\frac{3}{4}.44\frac{1}{5}$ 

$=\frac{3}{4}\left(26\frac{1}{5}-44\frac{1}{5}\right)$ 

$=\frac{3}{4}.\left(\frac{26.5+1}{5}-\frac{44.5+1}{5}\right)$ 

$=\frac{3}{4}.\left(\frac{131}{5}-\frac{221}{5}\right)$ 

$=\frac{3}{4}.\frac{131-221}{5}$ 

$=\frac{3}{4}.\frac{-90}{5}=\frac{3.(-90)}{4.5}$ 

$=\frac{\mathrm{3.5.2.}(-9)}{\mathrm{2.2.5}}=\frac{-27}{2}$ 

a) $\frac{3}{4}+\frac{2}{5}x=\frac{29}{60}$ 

$\frac{2}{5}x=\frac{29}{60}-\frac{3}{4}$ 

$\frac{2}{5}x=\frac{29}{60}-\frac{45}{60}$ 

$\frac{2}{5}x=\frac{-16}{60}$ 

$x=\frac{-16}{60}:\frac{2}{5}$ 

$x=\frac{-16}{60}.\frac{5}{2}$ 

$x=\frac{\mathrm{2.4.}(-2).5}{\mathrm{5.3.4.2}}$ 

$x=\frac{-2}{3}$ 

b) $\frac{4}{5}x-\frac{1}{2}.\frac{3}{2}=\frac{-9}{2}$ 

$\frac{4}{5}x-\frac{3}{4}=\frac{-9}{2}$ 

$\frac{4}{5}x=\frac{-9}{2}+\frac{3}{4}$ 

$\frac{4}{5}x=\frac{(-9).2}{4}+\frac{3}{4}$ 

$\frac{4}{5}x=\frac{-18}{4}+\frac{3}{4}$ 

$\frac{4}{5}x=\frac{-15}{4}$ 

$x=\frac{-15}{4}:\frac{4}{5}$ 

$x=\frac{-15}{4}.\frac{5}{4}$ 

$x=\frac{-75}{16}$