(a) at least 100 coupons are redeemed?

X>=100

N=5000 P= .0320

U=N*P= 5000 * .0320 = 160

Std Dev= Sqrt5000(.032)(.968) = 13.07

Z= 100 – 160/13.07 = -4.59

P(x >= 100) = P(z >= -4.59)

Now the problem I have is the z answer is well outside of the z chart to get the answer. Can someone please tell me what I did wrong?