Metric System Calculations For Nursing Part 2

Math Review Practice Questions cont. * LVNs who are NOT IV certified should stop here. All other nurses may want to practice #21 through #24. 21. Ordered: 120 mL to be infused over 30 minutes. At what rate (mL/hr) should the nurse set the infusion pump? mL/hr 22. Ordered: IV solution to run at 100 mL/hr. The IV tubing has a drip factor of 15 gtts/mL. How many gtts/min will need to be delivered? gtts/min 23. Ordered: 1000 mL D5W with 0.45% N/S in 6 hours How fast should the nurse run the IV in gtts/min if they are using tubing that delivers 15 gtts/mL? gtts/min 24. Ordered 20,000 units in 1000 mL to run at 30 mL/hour. How many units per hour is the patient receiving? units/hr Math Review Practice Questions (Answer Key) 1. Convert 99 lb to kg 99 lbs ÷ 2.2 = __45__ kg 2. Convert 4 mg to mcg 4 mg x 1000 = __4000__ mcg 3. Convert 2 gm to mg 2 gm x 1000 = __2000__ mg 4. Convert 300 mg to gm 300 gm ÷ 1000 = __ 0.3 __ gm 5. Convert 2500 mcg to mg 2500 mcg ÷ 1000 = ___2.5__ mg 6. Ordered: 40 units Available: 100 units/mL How many mL should the nurse give? 100 units = 40 units 1 mL X mL 100 units x X mL = 40 units x 1 mL X mL = 40 units x 1 mL 100 units ___0.4___ mL Math Review Practice Questions (Answer Key) cont. 7. Ordered: 0.125 mg Available: 0.25 mg/tablet How many tablet(s) should the nurse give? 0.25 mg = 0.125 mg 1 tablet X tablet(s) 0.25 mg x X tablet(s) = 1 tablet x 0.125 mg X tablet(s) = 1 tablet x 0.125 mg 0.25 mg __0.5_ tablet(s) 8. Ordered: 0.5 mg Available: 2 mg/mL How many mL should the nurse give? 2 mg = 0.5 mg 1 mL X mL 2 mg x X mL = 1 mL x 0.5 mg X mL = 1 mL x 0.5 mg 2 mg _ 0.25 _ mL 9. Ordered: 0.3 gm Available: 300 mg/tablet How many tablet(s) should the nurse give? 0.3 gm x 1000 = 300 mg 300 mg = 300 mg 1 tablet X tablet(s) 300 mg x X tablet(s) = 1 tablet x 300 mg X tablet(s) = 1 tablet x 300 mg 300 mg __1__ tablet(s) Math Review Practice Questions (Answer Key) cont. 10. Ordered: 0.03 gm Available: 6 mg/8 mL How many mL should the nurse give? 0.03 gm x 1000 = 30 mg 6 mg = 30 mg 8 mL X mL 6 mg x X mL = 8 mL x 30 mg 6 mg = 8 mL x 30 mg 6 mg __40_mL 11. Ordered: 80 mg Available: 100 mg/mL How many mL should the nurse give? 100 mg 1 mL = 80 mg X mL 100 mg x X mL = 1 mL x 80 mg X mL = 1 mL x 80 mg 100 mg _0.8__mL Math Review Practice Questions (Answer Key) cont. 12. Ordered: 250 mg Available: The bottle says add 9.5 mL of sterile water to the vial to yield 0.5 gm/mL How many mL should the nurse give? 0.5 gm = 500 mg 500 mg = 250 mg 1 mL X mL 500 mg x X mL = 1 mL x 250 mg X mL = 1 mL x 250 mg 500 mg _ 0.5 mL 0.4 mL 13. Ordered: 100,000 units Available: 250,000 units/mL How many mL should the nurse give? 250,000 units = 100,000 units 1 mL X mL 250,000 units x X mL = 1 mL x 100,000 units X mL = 1 mL x 100,000 units 250,000 units 14. Ordered: 75 mg Available: 50 mg/mL How many mL should the nurse give? 50 mg = 75 mg 1 mL X mL 50 mg x X mL = 1 mL x 75 mg X mL = 1 mL x 75 mg 50 mg 1.5 mL Math Review Practice Questions (Answer Key) cont. 15. Ordered: 70 mEq Available: 200 mEq/10 mL How many mL should the nurse give? 200 mEq = 70 mEq 10 mL X mL 200 mEq x X mL = 10 mL x 70 mEq X mL = 10 mL x 70 mEq 200 mEq 3.5 mL 16. Ordered: 0.6 mg Available: 250 mcg/mL How many mL should the nurse give? 0.6 mg x 1000 = 600 mcg 250 mcg = 600 mcg 1 mL X mL 250 mcg x X mL = 1 mL x 600 mcg X mL = 1 mL x 600 mcg 250 mcg 2.4 17. Ordered: 20 mg/kg for a patient who weighs 36 lb Available: 100 mg/mL How many mL should the nurse give? 36 lb ÷ 2.2 = 16.36 kg (rounded down to 16 kg or rounded up to 16.4 kg) 20 mg x 16.36 kg = 327.2 mg 100 mg = 327.2 mg 1 mL X mL 100 mg x X mL = 1 mL x 327.2 mg X mL = 1 mL x 327.2 mg 100 mg mL 3.27 mL (Rounds to 3.3 mL) Math Review Practice Questions (Answer Key) cont. 18. If your patient took 1 tsp of liquid every 15 minutes for 3 hours, how much total liquid was consumed in mL? 1 tsp x 5 = 5 mL 3 hours x 60 = 180 min 5 mL = 15 min X mL 180 min 15 min x X mL = 5 mL x 180 min X mL = 5 mL x 180 min 15 min 60 mL 19. Ordered: 25 mL every 2 hours. How many mL will be given in 8 hours? 25 mL = X mL 2 hrs 8 hrs 2 hrs x X mL = 25 mL x 8 hrs X mL = 25 mL x 8 hrs 2 hrs 100 mL 20. Ordered: 4 mg/kg for patient who weighs 55 kg Available: 90 mg in 10 mL How many mL should the nurse give? 4 mg x 55 kg = 220 mg 90 mg = 220 mg 10 mL X mL 90 mg x X mL = 10 mL x 220 mg X mL = 10 mL x 220 mg 90 mg __24.44 _ mL (Rounds to 24.4 mL) Math Review Practice Questions (Answer Key) cont. * LVNs who are NOT IV certified should stop here. All other nurses may want to practice #21 through #24. 21. Ordered: 120 mL to be infused over 30 minutes. At what rate (mL/hr) should the nurse set the infusion pump? 30 min ÷ 60 = 0.5 hr 120 mL = X mL 0.5 hr 1 hr 0.5 hr x X mL = 120 mL x 1 hr X mL = 120 mL x 1 hr 0.5 hr 240 mL/hr 22. Ordered: IV solution to run at 100 mL/hr. The IV tubing has a drip factor of 15 gtts/mL. How many gtts/min will need to be delivered? 1 hour x 60 = 60 mins X = Volume to be infused x Drip Factor of tubing time (in min) to be infused X gtts/min = 100 mL x 15 gtts/mL 60 min 25 gtts/min 23. Ordered: 1000 mL D5W with 0.45% N/S in 6 hours How fast should the nurse run the IV in gtts/min if they are using tubing that delivers 15 gtts/mL? 6 hours x 60 =360 min X = Volume to be infused x Drip Factor of tubing time (in min) to be infused X gtts/min = 1000 mL x 15 gtts/mL 360 min 41.6 gtts/min (Rounds to 42 gtts/min) Math Review Practice Questions (Answer Key) cont. 24. Ordered 20,000 units in 1000 mL to run at 30 mL/hour. How many units per hour is the patient receiving? 20,000 units = X units 1000 mL 30 mL 1000 mL x X units = 20,000 units x 30 mL X units = 20,000 units x 30 mL 1000 mL X units = 600,000 units 1000 600 units/hr Common Conversions 1 gm = 1000 mg To convert grams (gm) to milligrams (mg), move decimal point 3 places to right 1.0 1000.0 !!! or multiply grams (gm) by 1000 1 mg = 0.001 gm To convert milligrams (mg) to grams (gm), move decimal point 3 places to the left 1.0 0.001 """ or divide milligrams (mg) by 1000 1 mg = 1000 mcg To convert milligrams (mg) to micrograms (mcg), move decimal point 3 places to right 1.0 1000.0 !!! or multiply milligrams (mg) by 1000 1 mcg = 0.001 mg To convert micrograms (mcg) to milligrams (mg), move decimal point 3 places to the left 1.0 0.001 """ or divide micrograms (mcg) by 1000 1 kg = 2.2 lb To convert kilograms (kg) to pounds (lb), multiply kg by 2.2 To convert pounds (lb) to kilograms (kg), divide lb by 2.2 1 tsp = 5 mL To convert teaspoon (tsp) to milliliters (mL), multiply tsp by 5 or ½ tsp = 2.5 mL 1 gr = 60 mg To convert grains (gr) to milligrams (mg) multiply by 60 ½ gr = 30 mg To convert mg to grains (gr) divide grains by 60 Notes: Trailing zeroes are for illustration purposes only and should NOT be used in clinical practice.