How many covalent bonds are there between the two carbon atoms in butadiene?

Butadiene is H2C=C=CHCH3 ; This is one possible isomer.

There are 11 covlanet bonds.

H2C ' 2

C=C ' 2

C=C ' 2

CHCH3 ' 2

CH3 ' 3

So 2 + 2 + 2+ 2 + 3 = 11