How many positive numbers from 1 to 999 have the sum of

their digits equal to 8?

For ex. the sum of digits in the numbers 62, 431, ... are equal to 8.

45 positive numbers have the sum of their digits equal to 8

Step-by-step explanation:

given data

number = 1 to 999

sum n = 8

to find out

positive numbers

solution

we will choose number by this formula

(n+1) (n+2) / 2

here n is 8

so put this value we get number that

positive numbers = (n+1) (n+2) / 2

positive numbers = (8+1) (8+2) / 2

positive numbers = 90 / 2

so 45 positive numbers have the sum of their digits equal to 8