How many sigma and pi bonds in this molecule?

You need to be able to draw the molecule to show its bonding. The common name for this molecule is "isoprene". Use Google images to find a representation that shows isoprene's bonding.

For single bonds count one sigma; for double bonds count one sigma and one pi bond.

Don't forget to count the carbon-hydrogen (sigma) bonds in the -CH3 side chain. I get 12 sigma and 2 pi bonds in the whole molecule, but that was at a quick glance and you should check that I haven't made a mistake.

H2 in this formula means 2 H joined to 1 C, not H2 joined to 1 carbon.Trust you can see the difference.

Next H has single valency bond and C has 4

So the first carbon atom is joined the 2 hydrogens the carbon in the CH3 and the carbon in the CH group, giving a valency of 4. The C in the CH3 is joined to 3 hydrogens, and 1 C, so 4 again. These bonds are all simple single bonds, and so are sigma bonds.

Then it is CH joined to the previous carbon by a single bond, joined to another C, which has 2H attached to it. In this case both Cs have only 3 bonds accounted for. The result is a double bond between these 2 Cs. to make each 4, this is a pi bond, with the original sigma bond.

Hope that is clear.