The number that comprises 8+2+5 to form 10 is 5. This is because when you add 8, 2, and 5 together, the sum is 15. To form the number 10, you subtract 5 from 15, which leaves you with 10. This is a straightforward arithmetic operation that demonstrates the basic principles of addition and subtraction.

The reason this is possible is due to the fundamental nature of arithmetic operations. In mathematics, the addition of numbers is commutative, meaning that the order of the numbers being added does not affect the sum. This is expressed by the equation a + b = b + a. In the case of 8+2+5, the order of the numbers can be rearranged without changing the result. Additionally, subtraction is the inverse operation of addition, which allows for the formation of a specific number by removing a certain value from a larger sum.

Data supporting this concept can be found in various educational resources and textbooks that teach basic arithmetic. For instance, the National Council of Teachers of Mathematics (NCTM) emphasizes the importance of understanding the properties of operations, including commutativity and the relationship between addition and subtraction, in its standards for mathematical practice. According to the NCTM, these properties are foundational for students to develop a deeper understanding of number relationships and operations.

In conclusion, the number 5 is the result of the arithmetic operation 8+2+5 to form 10. This is due to the commutative property of addition and the inverse relationship between addition and subtraction. Educational resources such as those provided by the NCTM reinforce the importance of these mathematical principles in the development of students' computational skills.