even numbers: 2,4,6,8

odd numbers : 1,3,5,7,9

we have to form a number 5 digit number with 3 odd digits and two even digits

now number of ways in which 3 odd numbers can be taken=5C3

number of ways in which 2 even numbers can be taken=4C2

now number of ways of forming the number=5C3*4C2*5!

because each combination obtained can be written in 5! ways