Use a standard normal table to find the positive critical value that corresponds to a right tail area of 0.0250.025, rounding to three decimal places

Let the require value be x, then

P(z > x) = 0.025
1 - P(z < x) = 0.025
P(z < x) = 1 - 0.025 = 0.975
P(z < x) = P(z < 1.96)
x = 1.96

Therefore, the positive critical value that corresponds to a right tail area of 0.025 is 1.96

Ummm ok. for informing us