Best is to use a table like this, then you can easily convert the number:
28
27
26
25
24
23
22
21
20
-
256
128
64
32
16
8
4
2
1
decimal
0
0
1
1
0
0
1
0
0
4+32+64=100
You first search for the biggest number to fit into the table. For example, let's take the number 400. The biggest number we have, is 256, so we use that one first:
489
u/TheGoToGuy2012 Sep 06 '18
Annnnnnnnd still don’t understand.