Hi alexandrabel90,

The part in blue is the probability that when

for

In this case you need to work with the region in the tails of graph of the normal curve.

The 0.5% to the right of 99.5% added to the first 0.5%

constitutes the 1% region in a 2-tailed situation,

or the first 1% or last 1% (9% to 100%) constitutes the 1% region

in a 1-tail situation.