6.25 Запишите в виде десятичной дроби: 3 4 13 8 21 9 8 1 1 a) 5—, 7—, —, —, —, —; 10 10 100 100 100 100 100 1000 1000 7 9 19 407 1 б) 324—, —, —, —, —; 1000 10000 100 000 320 10000 1 8 9 в) 9—, —, —. 10 100 100 000 917 919 25 и —. 25

a)

• 5 \(\frac{3}{10}\) = 5 + \(\frac{3}{10}\) = 5 + 0.3 = 5.3;
• 7 \(\frac{4}{10}\) = 7 + \(\frac{4}{10}\) = 7 + 0.4 = 7.4;
• \(\frac{13}{100}\) = 0.13;
• \(\frac{8}{100}\) = 0.08;
• \(\frac{21}{100}\) = 0.21;
• \(\frac{9}{100}\) = 0.09;
• \(\frac{8}{1000}\) = 0.008;
• \(\frac{1}{1000}\) = 0.001;
• \(\frac{1}{100}\) = 0.01.

б)

• 324 \(\frac{7}{1000}\) = 324 + \(\frac{7}{1000}\) = 324 + 0.007 = 324.007;
• \(\frac{9}{10000}\) = 0.0009;
• \(\frac{19}{100000}\) = 0.00019;
• \(\frac{407}{320}\) = 1.271875;
• \(\frac{1}{10000}\) = 0.0001.

в)

• 9 \(\frac{1}{10}\) = 9 + \(\frac{1}{10}\) = 9 + 0.1 = 9.1;
• \(\frac{8}{100}\) = 0.08;
• \(\frac{9}{100000}\) = 0.00009;
• \(9\frac{17}{25}\) = \(9 + \frac{17}{25}\) = \(9 + \frac{17 \cdot 4}{25 \cdot 4}\) = \(9 + \frac{68}{100}\) = 9 + 0.68 = 9.68;
• \(9\frac{19}{25}\) = \(9 + \frac{19}{25}\) = \(9 + \frac{19 \cdot 4}{25 \cdot 4}\) = \(9 + \frac{76}{100}\) = 9 + 0.76 = 9.76.

Ответ: a) 5.3, 7.4, 0.13, 0.08, 0.21, 0.09, 0.008, 0.001, 0.01; б) 324.007, 0.0009, 0.00019, 1.271875, 0.0001; в) 9.1, 0.08, 0.00009, 9.68, 9.76