In response to msdobe :
I'm trying to calculaate 2 percentages:
1. H2/D2 * 100
2. G2+H2/D2 * 100

Paul Sheppard wrote:
For the second example 2. G2+H2/D2 * 100 - type =SUM(G2+H2)/D2
ansd again format the cell as a percentage

Pray tell, what does SUM(G2+H2) do that (G2+H2) would not do
equally well, if not better?

Moreover, it should be noted that G2+H2/D2 is ambiguous.
Paul interpreted it as (G2+H2)/D2, and he might very well
be right. But "msdobe" might have intended G2+(H2/D2).
No way to know.

In any case, the answer to all such questions is what you
said for the first case: format the cell with the number
category "percentage" and omit "* 100".

Since "msdobe" is obviously naive, it should be noted that
that the recommendation will result in cells whose physical
value contains the visible value divided by 100. For
example, if the cell appears to have 50%, its actual value
is 0.50.

Moreover, a side-effect of the formatting suggestion is
that all cells will have the "%" character. If "msdobe"
wants to avoid that, then return to the original expression
with "* 100" and properly parenthesize it.

Specifically, the second expression should be either
(G2+H2)/D2 * 100 or (G2 + H2/D2)*100, depending on intent.
There seems to be nothing wrong with the first expression,
in this respect.