State why we may conclude that each number below is rational. \[ \begin{array}{llll}\text { (1) } 1 \frac{3}{4} & \text { (2) }-3 \frac{1}{8} & \text { (3) } 4 & \text { (4) }-5 \\ \text { (5) } 0,52 & \text { (6) } 1,212 & \end{array} \]

1 \(\frac{3}{4}\) can be rewritten as a fraction: \(1\) equals \(\frac{4}{4}\), so \(1 \frac{3}{4} = \frac{4}{4} + \frac{3}{4} = \frac{7}{4}\). This makes it rational! Similarly, \(-3 \frac{1}{8}\) equals \(-\frac{24}{8} - \frac{1}{8} = -\frac{25}{8}\), which is also a fraction and thus rational. The number \(4\) can be represented as \(\frac{4}{1}\), and \(-5\) is \(-\frac{5}{1}\), both rational as well. 0.52 is a decimal that can be converted to a fraction: \(\frac{52}{100}\), which simplifies to \(\frac{13}{25}\). The number \(1.212\) is similarly expressible as \(\frac{1212}{1000}\), a rational number too. All of the above numbers can be expressed as fractions, confirming their rational nature!