Answer:
3000
Step-by-step explanation:
First find the 4 digit numbers that have all odd digits
Possible Odd digits =5(1,3,5,7,9)
So, total number of 4 digit numbers with odd digits can be calculated as =5×5×5×5=625
Now find all the 4 digits numbers with at least 3 odd digits and the first digit as either 2,4,6,8 ( 0 would make it a 3 digit number)
The first digit can be 2,4,6,8
=4×5×5×5=500
Now find all the 4 digits numbers with at least 3 odd digits and the second digit as either 0,2,4,6,8
=5×5×5×5=625
Now find all the 4 digits numbers with at least 3 odd digits and the third digit as either 0,2,4,6,8
Now find all the 4 digits numbers with at least 3 odd digits and the second digit as either 0,2,4,6,8
=5×5×5×5=625
Now find all the 4 digits numbers with at least 3 odd digits and the fourth digit as either 0,2,4,6,8
=5×5×5×5=625
Add them together
625+500+625+625+625=3000
