Let A equal the number of four digit odd numbers. Let B equal the number of four digit multiples of 7. Find A + B.
Between 1,000 and 9,999 =9,000 four-digit numbers.
A =9,000 / 2 = 4,500 Odd numbers.
B =9,000 / 7 =1,286 multiples of 7
[A + B] = [4,500 + 1,286] =5,786
