standard_description: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
problem_activity: Task
Chavone is remodeling her bathroom.  She plans to cover the bathroom floor with tiles that are each 1 square foot.  Her bathroom is $5\frac12$ feet wide and $8\frac14$  feet long.
How many tiles will she need to cover the floor? Give an exact answer that includes the fractions of a tile she will need. Each unit square has been broken into sixteenths to allow precise measurements. Use the figure below to illustrate your answer.
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aligns: no