Final answer:
The decimal 5.42 can be written as a mixed number 5 21/50 in simplest form by breaking it into a whole number and a fraction then simplifying the fraction.
Step-by-step explanation:
The decimal 5.42 can be broken down into a whole number and a decimal part. The whole number is 5 and the decimal part is .42. To express .42 as a fraction, we consider it as 42 hundredths, which can be written as 42/100. This fraction can be simplified by dividing both the numerator and the denominator by their greatest common divisor, which is 2. After simplification, we get 21/50. Therefore, the mixed number is 5 and 21/50.