Short cuts to problems problems

sharksfan

Hello All,
In the EPS section in the Income statement section, a quick way to determine if the convertible debt is dilutive is to simply calculate:
conv. debt interest (1-tax) / conv. debt shares.
If this is > basic EPS then not dilutive.

Similar short cuts must be all around the place but I simply can't seem to recollect them. I know there is one regarding a ratio in the Fixed Income/Derivatives/Alt Investments section. Something where a simply addition would give an answer of (say) 3 while the "proper" procedure would give 2.999. Anybody know what I am talking about?
Things like these are great time savers.
Could you please share similar things that you came across?
Thanks!
P