Estimate and then find the product of 12×5.2

12 x 5.2

Estimate:
since 5.2 is about 5, we can estimate this to:
12 x 5 = 60

Find the Product: 
    
        12
  x    5.2  
        2 4
  +  6 0 0
       6 2 4

now add the decimal back in. In the original problem there is one decimal place (the .2 in 5.2) so we move the decimal place one over in our product

624 becomes 62.4

The middle 99.7% of data in a normal distribution is the range from µ – 3σ to µ + 3σ. The standard deviation is 55, so 3σ = 3 ∙ 55 or 165. Therefore, the range of values in the middle 99.7% is 251 < X < 581.