excel functions in vb.net

Hi All,
I want to do some calculating in vb.net and for this I would like to know if there are simular functions that I used to use in excel available in VB.net
what I am looking for is sum.ifs count ifs and if count formula's

what I would like to achieve is the following

calculate the average of my cars fuel consumption

for this I also want to calculate the difference between the average consumption messured by the boardcomputer and the average consumption calculated by myself.

I also calculate the average consumption on summer and winter tyres

in excel I use the following functions

=IF(count(data!$F14:$G14)=2;data!$F14/data!$G14-1;"") to calculate the difference in % between the real consumation and the consumation according to the board computer

=average.if(M2:M12;"Zomer";F2:F12)
=SOMPRODUCT(data!G14:G135;data!C14:C135)/B1

are there functions in vb that can replace the above functions

thanks for your help