There are 5 terms in this data set. This means that you must add all of the terms and divide by the amount of terms to get your mean.
The missing number will be represented by x. Set up the equation:
[tex] \frac{1 + 3 + 0 + 6 + x}{5} = 3 = \frac{10 + x}{5} = 3 [/tex]
Multiply both sides by 5 to get rid of the denominator:
[tex] 10 + x = 15 [/tex]
Subtract 10 from both sides to get x by itself:
[tex] \boxed{x = 5} [/tex]
The missing number of chicken nuggets will be 5.