Answer:
See below.
Explanation:
A measurement could be a distance or a length, or a weight, or a volume. All those quantities are expressed as positive numbers.
For example, what is the distance from New York to Los Angeles?
Answer: 2,800 miles
What is the length of a book?
Answer: 8 inches
How much does John weigh?
Answer: 150 lb
All those numbers are positive.
There is one measurement that is often a negative number. That is a temperature.