Working on Dimensional Analysis in Physics and having a problem understanding what it is im supposed to do when deterimining if the equation is dimensionally correct... here is an example of what im doing:

m/s = (m/s + m/s)/2

That one I dont seem to have a problem with (if I did it correctly...) simply multiply the 2 and then add the m/s's and they equal (therefore its dimensionally correct)

Im having trouble with ones like..

m/s = m/s^2 + 2(m/s^2)(m^2)
I can break it down a few steps but it doesn't end up to being equal.. so is this simply not dimensionally correct?
and
m = (1/2)(m/s)(s) + (m/s^2)(s)
ahh confusing...

I must not be getting what to do... the teacher was rushing at the bell so yeah dont know what im doing lol...

Anyone wanna help?
Thanks
Sac