### Instruction: Let $A$ equal the number of four digit odd numbers.  Let $B$ equal the number of four digit multiples of 5.  Find $A+B$. Please respond by writing a program in Python.### Response: # For a four digit number, the first digit can be any number from 1 to 9 (9 possibilities), 
# the middle two digits can be any number from 0 to 9 (10 possibilities each), 
# and the last digit can be any odd number i.e., 1, 3, 5, 7, 9 (5 possibilities).

A = 9 * 10 * 10 * 5

# For a four digit number to be a multiple of 5, the last digit should be either 0 or 5 (2 possibilities).
# The first digit can be any number from 1 to 9 (9 possibilities), 
# the middle two digits can be any number from 0 to 9 (10 possibilities each).

B = 9 * 10 * 10 * 2

# Add A and B to find the total number of four digit odd numbers and multiples of 5.

result = A + B

print(result)