Binary

I really suck at binary and I need to work out these sums and show the working but the answers keep coming out wrong:

00001111 + 00000011 = 00010000
00001111 – 00000011 = 00001100
00001111 * 00000011 = 00101101
00001111 / 00000011 = 00000101

00011001 + 00000101 = 00011001
00011001 – 00000101 = 00011110
00011001 * 00000101 = 011111101
00011001 / 00000101 = 00000101

00011100 + 00000100 = 00100000
00011100 – 00000100 = 00011000
00011100 * 00000100 = 01110000
00011100 / 00000100 = 00000111

Can anyone give me a bit of help?

EDIT: oh yeh I got the answers using a calculater I thought if I knew the answers first it would be easier to work out

i cant really help... to be honest i never understood it..Try going on a (i know this osunds steriotypical) but a nerdy computer site and just right it in there shout bit if they have one.They are sure to help

For lazyness purposes you may just want to convert em to standard deanary do the math then reconvert em to binary format "/

ok I get everything excdept the division now it also dosn't help I suck at long division with normal numbers :l