Equals to and CTL+=, and fraction numerator / denominator

Hello there,

Has been a long time since I use prime, but there is some shortcuts that Idon't know how to do it:

1. Equals to, like CTL + =

Its like impossibrl becouse o use = on my PC its SHIFT + 0, and I try CTL+SHIFT+0 and CTL+0, what i'm doing wrong?

One more thing, I have a fractions like 2/(2s+8), how can I choose numerator or denominator?

regards,

LL