which is correctect 9.90 or 9.9
Both 9.90 and 9.9 are correct, but they represent slightly different things.
9.90 is typically used when referring to a price or measurement that requires two decimal places. It shows that the number is accurate to the nearest hundredth.
9.9, on the other hand, may be used when referring to a whole number or when there is no need to specify the exact decimal value. It could represent a rounded number or a general estimate.