Em thích loại khác biệt có ý nghĩa vì nó đem lại cho ta những khác biệt thực sự, những khác biệt đáng trân trọng và đáng học hỏi.

Gọi số cần tìm là: \(\overline{abc}\)

Ta có:

\(\overline{2abc}\div\overline{abc}=17\)

\(2000\div\overline{abc}+\overline{abc}\div\overline{abc}=17\)

\(2000\div\overline{abc}+1=17\)

\(2000\div\overline{abc}=17-1\)

\(2000\div\overline{abc}=16\)

\(2000\div16=\overline{abc}\)

\(125=\overline{abc}\)

Vậy số cần tìm là: \(125\)

\(\dfrac{19}{25}+\left(-\dfrac{9}{5}\right)^2+\left(-4\right).\dfrac{2}{7}-\left(-2\right)^3\)

\(=\dfrac{19}{25}-\dfrac{81}{25}-\dfrac{8}{7}+8\)

\(=\dfrac{-62}{25}+\dfrac{8}{7}+8\)

\(=\dfrac{-234}{175}+8\)

\(=\dfrac{1166}{175}\)

0,7% = 7/1000

\(\dfrac{6}{5}\times43+\dfrac{6}{5}+\dfrac{6}{5}\times56\)

\(=\dfrac{6}{5}\times43+\dfrac{6}{5}+\dfrac{6}{5}\times1+\dfrac{6}{5}\times56\)

\(=\dfrac{6}{5}\times\left(43+1+56\right)\)

\(=\dfrac{6}{5}\times100\)

\(=120\)

\(12-x\div\dfrac{2}{3}=\dfrac{4}{5}\)

\(x\times\dfrac{3}{2}=12-\dfrac{4}{5}\)

\(x\times\dfrac{3}{2}=\dfrac{56}{5}\)

\(x=\dfrac{56}{5}\div\dfrac{3}{2}\)

\(x=\dfrac{112}{15}\)

Vậy \(x=\dfrac{112}{15}\)

\(\dfrac{x}{1.3}+\dfrac{x}{3.5}+...+\dfrac{x}{99.101}=50\)

\(\dfrac{3-1}{1.3}+\dfrac{5-3}{3.5}+...+\dfrac{101-99}{99.101}=50.\dfrac{2}{x}\)

\(1-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+...+\dfrac{1}{99}-\dfrac{1}{101}=\dfrac{100}{x}\)

\(1-\dfrac{1}{101}=\dfrac{100}{x}\)

\(\dfrac{100}{101}=\dfrac{100}{x}\)

\(\Rightarrow x=101\)

\(1+\dfrac{5}{15}\times\dfrac{2}{7}+\dfrac{1}{5}\times\dfrac{2}{7}\)

\(=1+\dfrac{1}{3}\times\dfrac{2}{7}+\dfrac{1}{5}\times\dfrac{2}{7}\)

\(=1+\dfrac{2}{7}\times\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)

\(=1+\dfrac{2}{7}\times\dfrac{8}{15}\)

\(=1+\dfrac{16}{105}\)

\(=1\dfrac{16}{105}\)

Lông vũ cậu nhé.