Question

The function that assigns every positive three-digit integer the sum of the largest and the smallest digits.

State the number of elements in the Domain and Range for this part only

Answer 1

Explanation:

The domain of this function consists of all positive three-digit integers. There are 900 three-digit integers in total, from 100 to 999 inclusive.

The range of this function consists of all integers between 2 and 18 inclusive, since the smallest and largest digits of a three-digit integer can range from 1 to 9, and their sum can range from 2 (1 + 1) to 18 (9 + 9). So the range has 17 elements in total: {2, 3, 4, ..., 18}.

Answer 2

17 numbers in this range.

Explanation:

For this function, the domain consists of all positive three-digit integers. There are 900 such integers, from 100 to 999.

The range consists of all numbers between 2 and 18, inclusive, since the smallest possible sum is 1+0+0 = 1 and the largest possible sum is 9+9+1 = 19, but the function only takes the sum of the largest and smallest digits. There are 17 numbers in this range.