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Convert pounds to kilograms, please help

Posted

Has 8 years experience.

Can you show me step by step an easy way of converting these.

9 lbs 6 ounces I put 4.47 Correct answer is 4.26

17lbs 14 ounces I put 8.61 Correct answer is 8.13

62lbs 12 ounces I put 28.93 Correct answer is 28.52

My method is obviously not working. I am always so close. Please help.

Thanks in advance...:crying2::crying2::cry:

Jolie, BSN

Specializes in Maternal - Child Health. Has 35 years experience.

Have you tried Googling "English metric conversion formulas"? Are you rounding to the the correct number of significant figures?

crazytonurse

Has 1 years experience.

Can you show me step by step an easy way of converting these.

9 lbs 6 ounces I put 4.47 Correct answer is 4.26

17lbs 14 ounces I put 8.61 Correct answer is 8.13

62lbs 12 ounces I put 28.93 Correct answer is 28.52

My method is obviously not working. I am always so close. Please help.

Thanks in advance...:crying2::crying2::cry:

well I obviously I am doing something wrong as well. I know 1kg = 2.2 lbs. so in my math I am coming up with different as well. I am interested in other answers.

ghillbert, MSN, NP

Specializes in CTICU. Has 20 years experience.

- 2.2 lbs in a kg.

- 28.35 g in an oz

9lb 6 oz:

- 9/2.2 = 4.09 kg

- 6 x 28.35 = 170g

So total = 4090 + 170 = 4260 g = 4.26kg

17lbs 14 ounces:

- 17/2.2 = 7.72kg

- 14 x 28.35 = 396.9g

Total = 8117g = 8.12kg

62lbs 12oz:

- 62/2.2 = 28.18kg = 28180g

- 12 x 28.35 = 340.2g

Total = 28520.2g = 28.52kg

JenRN30, BSN

Specializes in Endoscopy/MICU/SICU. Has 10 years experience.

Another quick way....

for 9 lbs 6 oz

6 oz out of 16 oz in a lb (6/16 = 0.375)

So, add 0.375 of a lb to 9 lbs = 9.375

9.375lbs /2.2 = 4.26 kg

for 17 lbs 14 oz

14/16 = 0.875

17.875/2.2 = 8.13

62 lbs 12 oz

12/16 = 0.75

62.75/2.2 = 28.52

deemarys

Has 8 years experience.

2 very different ways to get the answer, Wonder if there are other ways since 2 people still got 2 different answers for 8.13

deemarys

Has 8 years experience.

Another quick way....

for 9 lbs 6 oz

6 oz out of 16 oz in a lb (6/16 = 0.375)

So, add 0.375 of a lb to 9 lbs = 9.375

9.375lbs /2.2 = 4.26 kg

for 17 lbs 14 oz

14/16 = 0.875

17.875/2.2 = 8.13

62 lbs 12 oz

12/16 = 0.75

62.75/2.2 = 28.52

Thanks I will do it this way from now on.

Leesha

Specializes in Med/Surg. Has 7 years experience.

Hi,

You take the pounds divided by 2.2 and that will give you the kilograms.

Good Luck,

Leesha

tfleuter, BSN, RN

Specializes in ICU. Has 10 years experience.

2 very different ways to get the answer, Wonder if there are other ways since 2 people still got 2 different answers for 8.13

It's all about sig figs. Where one method starts you out with a "clean" number (14/16 = 0.875) the other starts out with a repeating decimal (17/2.2 = 7.272727272727272727272.....) Depending on where one chooses to round up the number (middle of the equation or at the end) will change the outcome. In either case, both are very close, but would be a concern if you needed to be exact up to the hundredths place.

thats weird because i get 17.14/2.2= 7.79=7.8 . I checked it on a converting program and the answer is still the same as mine. I have also passed all my math tests with 100% so I don't know what to say.

kdsrn

Specializes in Pediatric Heme/Onc and Pulmonary. Has 25 years experience.

I am a pediatric nursing instructor. The method used by JennieB30 is the most widely used method. I'm sorry RosssaysoonRN but your answer is incorrect.

Well until I get an instructor that tells me that 2.2lbs doesn't equal a Kilogram and all the books used that have taught me to do my math the way that I do then I'll continue to do them this way or unless all of a sudden I start failing my maths test then I am not wrong. There are many different ways to get a right answer.

thats weird because i get 17.14/2.2= 7.79=7.8 . I checked it on a converting program and the answer is still the same as mine. I have also passed all my math tests with 100% so I don't know what to say.

17 lbs 14 ounces =/= 17.14 lbs

tfleuter, BSN, RN

Specializes in ICU. Has 10 years experience.

Well until I get an instructor that tells me that 2.2lbs doesn't equal a Kilogram and all the books used that have taught me to do my math the way that I do then I'll continue to do them this way or unless all of a sudden I start failing my maths test then I am not wrong. There are many different ways to get a right answer.

The problem with the way you did your calculation is that 17lbs 14oz does not equal 17.14. That is why your answer came out differently.

ImMrBill3, RN

Specializes in ICU, Home Health Care, End of Life, LTC. Has 2 years experience.

This is a fairly common mistake. 17lbs 14 ounces IS NOT 17.14lbs IT IS 17 14/16 lbs.

An ounce is not a tenth of a pound but a sixteenth of a pound.

An easy way to conceptualize this is hours and minutes.

1 hour and 15 minutes IS NOT 1.15 hours IT IS 1 15/60 hours.

Other example include inches, feet and miles; ounces (liquid), pints, quarts and gallons.

Hope this helps, this is part of the reason for the change to the metric system (oh that's right we haven't changed because people are SOOO familiar with our system.)

kdsrn

Specializes in Pediatric Heme/Onc and Pulmonary. Has 25 years experience.

RossaysoonRN,

I'm not sure why you are getting so defensive. I was just trying to help demarys who asked a question. You are correct that 2.2 # is equal to 1 kg. What you did incorrectly was divide 17.14 by 2.2 instead of converting your oz to pounds 1st. You would first divide 14/16 to get 0.875. Add the 0.875 to 17 to get 17.875. Then divide 17.875 by 2.2. This is a very common mistake, but in pediatrics just a little bit off can make a significant difference in the dose.

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