You don't really need to find the range of the first standard deviation, you know...

First, define your variable.

Let X represent the IQ scores.

Then,

Standardize to the z value using:

a)

Then look in your table for this probability.

Same for the others.

b)

c)

d)

Well, since you did the range for the first standard deviation, the answer for the last one should be easier. What do you know about the probability of the central part of a normal curve bounded by one standard deviation on each side from the mean?