Multiplying Decimals: Common Mistake?

  • Context: High School 
  • Thread starter Thread starter BogMonkey
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Discussion Overview

The discussion revolves around the multiplication of decimals, specifically focusing on the confusion arising from multiplying measurements in different units (meters and centimeters) and the resulting units of area. Participants explore the implications of unit conversion and dimensional analysis.

Discussion Character

  • Conceptual clarification, Technical explanation

Main Points Raised

  • One participant expresses confusion about the multiplication of 0.5 meters by 0.5 meters resulting in 0.25 meters, questioning their understanding of the operation.
  • Another participant clarifies that 0.5m multiplied by 0.5m results in 0.25m², while 50cm multiplied by 50cm results in 2500cm², correcting the initial misunderstanding about the calculations.
  • A further contribution explains the relationship between meters and centimeters, noting that 1 m equals 100 cm and that the area conversion from square meters to square centimeters involves squaring the conversion factor.
  • The initial poster acknowledges the clarification provided by others, indicating a better understanding of the concepts discussed.

Areas of Agreement / Disagreement

Participants generally agree on the correct application of unit conversion and dimensional analysis, with no significant disagreement noted in the clarifications provided.

Contextual Notes

Limitations: The discussion does not explore the broader implications of dimensional analysis beyond the specific examples provided, nor does it address potential misunderstandings related to the initial calculations.

BogMonkey
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This is probably a stupid question but I'm fairly confused about this. If I multiply 0.5 meters by 0.5 meters I get 0.25 meters. If I multiply 50 cm by 50 cm I get 250 cm (2.5 meters). What mistake am I making here?
 
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0.5m * 0.5m = 0.25m²

50cm * 50cm = 2500cm²

0.25m² = 2500cm²

Your mistakes: 50*50 does not equal 250 and m*m does not equal m
 
To add to this:

1 m = 100 cm

(1 m)2 = (100 cm)2

1 m2 = 10000 cm2
 
Ah yeah that explains it. Thanks a lot.
 

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