How do I solve this? I know the answers but how do I get them?

How do I solve this? I know the answers but how do I get them?

10.       Draw a graph for the standard normal distribution. Label the horizontal axis at values of −3, −2, −1, 0, 1, 2, and 3. Then use the table of probabilities for the standard normal distribution inside the front cover of the text to compute the following probabilities. 

a.         P(z ≤ 1.5)

b.         P(z≤1) 

c.          P(1≤z≤1.5) 

d.         P(0<z<2.5)