Bài 2: Số thực. Giá trị tuyệt đối của một số thực
Hướng dẫn Giải Bài 2 (Trang 38, SGK Toán 7, Tập 1, Bộ Chân Trời Sáng Tạo)
<p><strong>B&agrave;i 2 (Trang 38, SGK To&aacute;n 7, Tập 1, Bộ Ch&acirc;n Trời S&aacute;ng Tạo)</strong></p> <p>Sắp xếp c&aacute;c số thực sau theo thứ tự từ nhỏ đến lớn"</p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mo>-</mo><mfrac><mn>2</mn><mn>3</mn></mfrac><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mn>4</mn><mo>,</mo><mn>1</mn><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>-</mo><msqrt><mn>2</mn></msqrt><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mn>3</mn><mo>,</mo><mn>2</mn><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mi mathvariant="normal">&#960;</mi><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>-</mo><mfrac><mn>3</mn><mn>4</mn></mfrac><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mfrac><mn>7</mn><mn>3</mn></mfrac><mo>.</mo></math></p> <p>&nbsp;</p> <p><strong><span style="text-decoration: underline;"><em>Hướng dẫn giải:</em></span></strong></p> <p>Ta c&oacute;:&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>2</mn><mn>3</mn></mfrac><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mo>&#160;</mo><mo>(</mo><mn>6</mn><mo>)</mo><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mn>4</mn><mo>,</mo><mn>1</mn><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>-</mo><msqrt><mn>2</mn></msqrt><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mn>1</mn><mo>,</mo><mn>414</mn><mo>.</mo><mo>.</mo><mo>.</mo><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mn>3</mn><mo>,</mo><mn>2</mn><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mi mathvariant="normal">&#960;</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>3</mn><mo>,</mo><mn>141</mn><mo>.</mo><mo>.</mo><mo>.</mo><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>-</mo><mfrac><mn>3</mn><mn>4</mn></mfrac><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>-</mo><mn>0</mn><mo>,</mo><mn>75</mn><mo>;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mo>&#160;</mo><mfrac><mn>7</mn><mn>3</mn></mfrac><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mn>2</mn><mo>,</mo><mo>(</mo><mn>3</mn><mo>)</mo><mo>.</mo></math></p> <p>Do -1,414... &lt; -0,75 &lt; 0,(6) &lt; 2,(3) &lt; 3,141... &lt; 3,2 &lt; 4,1</p> <p>N&ecirc;n&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>-</mo><msqrt><mn>2</mn></msqrt><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mo>-</mo><mfrac><mn>3</mn><mn>4</mn></mfrac><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mfrac><mn>2</mn><mn>3</mn></mfrac><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mfrac><mn>7</mn><mn>3</mn></mfrac><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mi mathvariant="normal">&#960;</mi><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mn>3</mn><mo>,</mo><mn>2</mn><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mn>4</mn><mo>,</mo><mn>1</mn><mo>.</mo></math></p>
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