I'm trying to do this problem and getting it wrong each time. Please help me understand where Im making my mistake.

I'm going 1.96 times 64.3= 126.028. I'm confused. Pleas help.

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately =64.3. You would like to be 95% confident that your estimate is within 5 of the true population mean. How large of a sample size is required? Use a z*=1.96 for this problem.