Bài tập cuối chương 2
Hướng dẫn Giải Bài 1 (Trang 45, SGK Toán 7, Tập 1, Bộ Chân Trời Sáng Tạo)
<p><strong>B&agrave;i 1 (Trang 45 SGK To&aacute;n 7, Tập 1 - Bộ Ch&acirc;n Trời S&aacute;ng Tạo):</strong></p> <p>Viết c&aacute;c ph&acirc;n số sau dưới dạng số thập ph&acirc;n:</p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mfrac><mn>5</mn><mn>16</mn></mfrac><mo>;</mo><mo>&#160;</mo><mfrac><mrow><mo>-</mo><mn>7</mn></mrow><mn>50</mn></mfrac><mo>;</mo><mo>&#160;</mo><mfrac><mn>11</mn><mn>40</mn></mfrac><mo>;</mo><mo>&#160;</mo><mfrac><mn>9</mn><mn>200</mn></mfrac><mo>;</mo></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>7</mn></mfrac><mo>;</mo><mo>&#160;</mo><mfrac><mn>1</mn><mn>11</mn></mfrac><mo>;</mo><mo>&#160;</mo><mfrac><mn>3</mn><mn>13</mn></mfrac><mo>;</mo><mo>&#160;</mo><mo>-</mo><mfrac><mn>5</mn><mn>12</mn></mfrac><mo>.</mo></math></p> <p>&nbsp;</p> <p><span style="text-decoration: underline;"><em><strong>Hướng dẫn giải:</strong></em></span></p> <p>a) Ta c&oacute;:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/11-zw2WJZ.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>5</mn><mn>16</mn></mfrac><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>3125</mn></math></p> <p>Ta c&oacute;:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/12-doiSIu.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mrow><mo>-</mo><mn>7</mn></mrow><mn>50</mn></mfrac><mo>=</mo><mo>-</mo><mn>0</mn><mo>,</mo><mn>14</mn></math></p> <p>Ta c&oacute;:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/13-X6wHmV.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>11</mn><mn>40</mn></mfrac><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>275</mn></math></p> <p>Ta c&oacute;:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/14-fqxvET.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>9</mn><mn>200</mn></mfrac><mo>=</mo><mn>0</mn><mo>,</mo><mn>045</mn></math></p> <p>b) Ta c&oacute;:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/15-WKMcbW.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>1</mn><mn>7</mn></mfrac><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>142857142857</mn><mo>.</mo><mo>.</mo><mo>.</mo><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mo>(</mo><mn>142857</mn><mo>)</mo></math></p> <p>Ta c&oacute;:<br /><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/16-hna6WD.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>1</mn><mn>11</mn></mfrac><mo>=</mo><mn>0</mn><mo>,</mo><mn>0909</mn><mo>.</mo><mo>.</mo><mo>.</mo><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mo>(</mo><mn>09</mn><mo>)</mo></math></p> <p>Ta c&oacute;:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/17-nOEE0Y.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>3</mn><mn>13</mn></mfrac><mo>=</mo><mn>0</mn><mo>,</mo><mn>230769230769</mn><mo>.</mo><mo>.</mo><mo>.</mo><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mo>(</mo><mn>230769</mn><mo>)</mo></math></p> <p>Ta c&oacute;:&nbsp;</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/29052022/18-rTKknv.png" /></p> <p>Vậy&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>5</mn><mn>12</mn></mfrac><mo>=</mo><mn>0</mn><mo>,</mo><mn>4166</mn><mo>.</mo><mo>.</mo><mo>.</mo><mo>=</mo><mo>&#160;</mo><mn>0</mn><mo>,</mo><mn>41</mn><mo>(</mo><mn>6</mn><mo>)</mo></math></p>
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