Mason is tiling the floor of his bathroom, which measures 9.75 feet by 8.63 feet. He estimates the area. Will he have enough tile if he buys 90 square feet of tiles? Explain why or why not.


  1. Answer: Yes he should have enough
    9.75 rounds up to 10
    8.63 rounds up to 9
    Then we can see that 10*9 = 90 is likely where Mason is getting that value from. Since we rounded up both times, this means that 90 is an overestimate of the area. The true area is something smaller
    Use a calculator to see the true area is 9.75*8.63 = 84.1425 square feet, which is smaller than 90. This confirms that 90 sq ft is indeed an overestimate and leads to the conclusion that he should have enough tiles.
    Side note: This assumes that Mason does not make too many mistakes in tiling the floor (or is perfect). This is why it’s better to overestimate rather than underestimate.


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