Lou Sr 3 cookies from the jar, then another three, but then put two back, for a total of 3+3-2=<<3+3-2=4>>4 cookies removed.
Louie Jr took seven more out of the jar, for a total of 4+7=<<4+7=11>>11 cookies removed.
If Debra thought half were gone, then the number of missing cookies would equal the number of cookies that remain, or 11 missing=11 remaining cookies
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