Đề thi giữa kì 2 Toán 6 Chân trời sáng tạo – Đề 1 (có đáp án)

a) $\frac{3}{4}:(\frac{-7}{5}.\frac{-3}{2})$ 

$=\frac{3}{4}:\frac{(-7).(-3)}{5.2}=\frac{3}{4}:\frac{21}{10}$ 

$=\frac{3}{4}.\frac{10}{21}=\frac{3.10}{4.21}=\frac{30}{84}$ 

$=\frac{30:6}{84:6}=\frac{5}{14}$ 

b) $\frac{-1}{9}.\frac{3}{5}+\frac{-1}{9}.\frac{-4}{5}-\frac{1}{9}.0,4$ 

$=\frac{1}{9}.\frac{-3}{5}+\frac{1}{9}.\frac{4}{5}-\frac{1}{9}.\frac{2}{5}$ 

$=\frac{1}{9}.(\frac{-3}{5}+\frac{4}{5}-\frac{2}{5})$ 

$=\frac{1}{9}.\frac{(-3)+4-2}{5}$ 

$=\frac{1}{9}.\frac{-1}{5}=\frac{1.(-1)}{9.5}=\frac{-1}{45}$

a) $0,25x-\frac{1}{3}=\frac{-5}{3}$ 

$0,25x=\frac{-5}{3}+\frac{1}{3}$ 

$0,25x=\frac{(-5)+1}{3}$ 

$0,25x=\frac{-4}{3}$ 

$x=\frac{-4}{3}:0,25$ 

$x=\frac{-4}{3}:\frac{1}{4}$ 

$x=\frac{-4}{3}.\frac{4}{1}$ 

$x=\frac{-16}{3}$ 

b) $(\frac{2}{3}x+\frac{1}{2}).\frac{-5}{6}=3$ 

$\frac{2}{3}x+\frac{1}{2}=3:\left(\frac{-5}{6}\right)$ 

$\frac{2}{3}x+\frac{1}{2}=3.\left(\frac{6}{-5}\right)$ 

$\frac{2}{3}x+\frac{1}{2}=\frac{3}{1}.\frac{6}{-5}$ 

$\frac{2}{3}x+\frac{1}{2}=\frac{18}{-5}$ 

$\frac{2}{3}x=\frac{18}{-5}-\frac{1}{2}$ 

$\frac{2}{3}x=\frac{18.2}{(-5).2}-\frac{1}{2.(-5)}$ 

$\frac{2}{3}x=\frac{36}{-10}-\frac{1}{-10}$ 

$\frac{2}{3}x=\frac{35}{-10}$ 

$x=\frac{35}{-10}:\frac{2}{3}$ 

$x=\frac{35}{-10}.\frac{3}{2} x=\frac{\mathrm{5.7.3}}{5.(-2).2} x=\frac{21}{-4}$ 

Ta có: $\frac{1}{50}>\frac{1}{100}$ 

$\frac{1}{51}>\frac{1}{100}$ 

....

$\frac{1}{98}>\frac{1}{100}$ 

$\frac{1}{99}>\frac{1}{100}$