1. The problem is to understand or work with the number 3.45. 2. Since no specific operation or question is given, let's consider the number as a decimal. 3. A decimal number like 3.45 means 3 units and 45 hundredths. 4. It can be expressed as a fraction: $$3.45 = 3 + \frac{45}{100} = \frac{345}{100}$$. 5. This fraction can be simplified by dividing numerator and denominator by 5: $$\frac{345}{100} = \frac{69}{20}$$. 6. So, 3.45 is equivalent to the fraction $$\frac{69}{20}$$. 7. If you want to perform any operation or need further explanation, please specify.