Binary value of 30 decimal number
Result
30 = 11110
Explained

30 / 2 = 15
0 remainder of division 
15 / 2 = 7.5
1 remainder of division 
7 / 2 = 3.5
1 remainder of division 
3 / 2 = 1.5
1 remainder of division 
1 / 2 = 0.5
1 remainder of division
Read listed remainders in reverse:
30 = 11110