I am finding it difficult to understand how to best tackle the mathematical aspects of the long response questions.

Is it best to write down the formulas on a piece of paper and then substitute the numbers to the formula on the screen of the computer?

For example for the blended tax approach

wartr = ri*ti + rd*td + rrcg*trcg
r* = r(1-wartr)

T*=tcg(portion of deferred cap gains/(1-wartr))

FVFAT = ((1+r*)^n)*(1-T*) + T* - (1-B)tcg

the above on paper and then plug the numbers in on the computer screen?

is this the best way?