To convert grams to milligrams, you need to multiply by 1,000 because there are 1,000 milligrams (mg) in 1 gram.So, to convert 13.8 grams to milligrams:13.8 g×1,000 mg/g=13,800 mg13.8g×1,000mg/g=13,800mgNow, let's write this result in scientific notation. Scientific notation represents a number as a coefficient (between 1 and 10) multiplied by a power of 10.The number 13,800 can be written in scientific notation as:1.38×104 mg1.38×104mgSo, the hemoglobin concentration of 13.8 g/dL is equivalent to 1.38 x 10^4 mg/dL when expressed in scientific notation.