Question 178935
Find the {{{range}}} of the measurements: {{{40-0.05 = 39.95 mg}}}
Find the {{{mid-point}}} of that range: {{{(40+0.05)/2 = 20.025}}} 
Find the {{{distance}}} from the {{{mid-point}}} to an {{{end}}}{{{ point}}}:
{{{40-20.025 = 19.075}}}
-----------------
Let {{{x}}} be one of the measures in the proper range:
|{{{x-20.025}}}| < {{{19.075}}}
This describes all the measurements that are within {{{19.075}}} of {{{20.025}}}.