Multiplying Decimals: Common Mistake?

  • Thread starter BogMonkey
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In summary, the most common mistake people make when multiplying decimals is forgetting to align the decimal points. To avoid making mistakes, it is important to carefully align the decimal points, use the appropriate number of decimal places, and double check your work. The same rules for multiplying whole numbers apply when multiplying decimals, but it is important to account for the decimal point. If your answer has a different number of decimal places, you should round it to the appropriate number. It is not necessary to convert decimals to fractions before multiplying them, as you can simply multiply them as they are.
  • #1
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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  • #2
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
 
  • #3
To add to this:

1 m = 100 cm

(1 m)2 = (100 cm)2

1 m2 = 10000 cm2
 
  • #4
Ah yeah that explains it. Thanks a lot.
 

FAQ: Multiplying Decimals: Common Mistake?

What is the most common mistake people make when multiplying decimals?

The most common mistake people make when multiplying decimals is forgetting to align the decimal points. This can lead to incorrect answers.

How can I avoid making mistakes when multiplying decimals?

To avoid making mistakes when multiplying decimals, it is important to carefully align the decimal points and use the appropriate number of decimal places in the final answer. It may also be helpful to double check your work using a calculator or by using estimation to ensure that your answer is reasonable.

Can I use the same rules for multiplying whole numbers when multiplying decimals?

Yes, the same rules for multiplying whole numbers apply when multiplying decimals. However, it is important to remember to account for the decimal point and use the appropriate number of decimal places in the final answer.

What should I do if I get a different number of decimal places in my answer compared to the original numbers?

If you get a different number of decimal places in your answer compared to the original numbers, you should round your answer to the appropriate number of decimal places. This may require adding zeros at the end of your answer or dropping excess digits.

Is it necessary to convert decimals to fractions before multiplying them?

No, it is not necessary to convert decimals to fractions before multiplying them. You can simply multiply the decimals as they are, being careful to align the decimal points and use the appropriate number of decimal places in the final answer.

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