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• Specializes in psych,and detox,and Ltc.

Hello all,I'm getting ready to start my second semester of nursing school of the 22th of this month. Eash semester we must take a calculations exam....I have always had problems when it came to problems with grains......I'm looking over my practice exam..and dont have a clue how to set up or do this grains problem....can someone show me how to set up grains problems..and how to solve them.

My school uses the formula.....gr i = 60 mg or gr vx = 1000mg.

Here is the problem.

Order NTG gr 1/150 IV stat. Available: NTG 0.4 mg/ml. How many ml's will you give?

Any help would be a blessing....Thanks all.

1,547 Posts

Specializes in Wound Care, LTC, Sub-Acute, Vents. Has 5 years experience.
hello all,i'm getting ready to start my second semester of nursing school of the 22th of this month. eash semester we must take a calculations exam....i have always had problems when it came to problems with grains......i'm looking over my practice exam..and dont have a clue how to set up or do this grains problem....can someone show me how to set up grains problems..and how to solve them.

my school uses the formula.....gr i = 60 mg or gr vx = 1000mg.

here is the problem.

order ntg gr 1/150 iv stat. available: ntg 0.4 mg/ml. how many ml's will you give?

any help would be a blessing....thanks all.

= (1/150) x (60 mg) (cancel the zero)

= (1/15) x (6)

=6/15

=2/5

=0.4 mg ( same as gr 1/150, the original order)

then (0.4 mg / 0.4 mg) x 1 ml

so, you would give 1 ml

3,723 Posts

Has 10 years experience.
= (1/150) x (60 mg)

= (1/15) x (6)

=6/15

=2/5

=0.4 mg

then (0.4mg / 0.4 mg) x 1 ml

so, you would give 1 ml

:yeahthat: your fingers were quicker than mine

168 Posts

Specializes in psych,and detox,and Ltc.

I tried 150 x 60 and I got 9000

so what am I doing wrong.

I see what you did But just dont get the hang on it....I feel so dump.

Where is 1/15 x 6 coming from???

1,547 Posts

Specializes in Wound Care, LTC, Sub-Acute, Vents. Has 5 years experience.
i tried 150 x 60 and i got 9000

so what am i doing wrong.

i see what you did but just dont get the hang on it....i feel so dump.

where is 1/15 x 6 coming from???

= 1 ... .. 60

---- x -----

150 ...... 1

= (1 x 60)

-----------

(150 x 1)

= 60 / 150

= 6 / 15 ( i just cancelled the zero to make the number smaller)

29 Posts

wow I had a nice long explanation, then I realized someone replied..

3,723 Posts

Has 10 years experience.

think of it a sixty over 1 times 1 over 150..

60 x 1

1 150

you can reduce the 60 down to 5 (after you divide by 10) and 150 down to 15 (after you divide by 10)

then it reads on 1 over 15 times 6 over 1 giving you 6 over 15. You can either reduce 6/15 to 2/5 or leave it the way it is. Either way, then divide the bottom number into the top and thats your conversion.. 0.4mg=1/150grains

168 Posts

Specializes in psych,and detox,and Ltc.

can I do this with all grains problems???....is so I think I got it:w00t: You guys make it sound soooo easy......thank you hats off to all.....

1,547 Posts

Specializes in Wound Care, LTC, Sub-Acute, Vents. Has 5 years experience.
can i do this with all grains problems???....is so i think i got it:w00t: you guys make it sound soooo easy......thank you hats off to all.....

yes, what ever the grain(s), you multiply it by 60 / 1 (sixty over one).

and try to always reduce your number to a smaller one so that it would be easier to solve (if you are allowed to use a calculator then you don't have to).

angel

3,723 Posts

Has 10 years experience.

Yup, do the exact same thing for any other grain conversion. Oh, a way our instructor had use memorize/remember grains to mg or vise versa was..draw a clock face..on the inside put the numbers like they'd correspond with the clock..for example put 15 where quarter after would be 30 where 1/2 hr would be 45 where quarter of would be and 60 where the hour would be..now on the outside next to the the 15 put 1/4 (quarter past the hour), at the 30 put 1/2 (half past the hour) at the 45 put 3/4 (three quarters of an hour) and at the 60 put 1 (hour). guess what you now have..yup the grain to milligram or milligram to grain conversions. look at the clock. 15mg is 1/4 grain, 30milligrams is 1/2 grain, 45mg is 3/4 grain and 60mg is 1 grain!

Ever dose calc test I take, I immediately put the clock face down :)

168 Posts

Specializes in psych,and detox,and Ltc.

thanks sooooooo much...life seems so much easier now..... can now do grain problems.......THANK The LORD......I wish I knew it was that easier last semester.:w00t::w00t::w00t:

1 Article; 2,396 Posts

Specializes in Ortho, Neuro, Detox, Tele.

ok, I have another way to do it...if you want to hear....

Order NTG gr 1/150 IV stat. Available: NTG 0.4 mg/ml. How many ml's will you give?

You know 1gr = 60mg.............

so..... (1/150)= (60/150) = 0.4 mg x 1ml = 0.4 ml.....

you take your dose desired 0.4mg

OVER your dose on hand 0.4mg

multiply the whole thing by your volume 1ml

DD x ? ml = mg/ml......

DOH

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