How to calculate hard money cost without an excel calculator?

[Jordan Ray]

How is it going? I am a realtor & real estate investor in the Memphis, TN market. I suck at math & I am trying to calculate how to paper analyze a BRRRR deal with hard money without using excel. Does anyone know a simple way to calculate this? 

ARV x 70% - repairs - (hard money cost) I assume but how do I break down those costs?

I have rental property now but I have never used hard money like we have it here in our market with some of our local lenders being at 100% of the purchase & 100% of the rehab just pay closings costs like points (Which are very expensive at 5 points & 12-13% interest with this method)

I am just having a hard time trusting that I am calculating this correctly... either that or I am over thinking it.

Thanks in advance!