The expression you've provided appears to represent a range for the rate of human hair growth. However, it seems incomplete or improperly formatted.
Typically, human hair grows at an average rate of about 0.5 inches (1.25 cm) per month, which translates to approximately 6 inches (15 cm) per year.
If your expression is meant to indicate growth in a scientific notation format, it may represent a range of growth rates, possibly in meters or another unit. For clarification, can you specify what the values in your expression represent or if you have a specific question related to hair growth rates?