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1Formulas and methods
Nursing assistant (CNA) knowledge
Method
Check whether the resident is in danger right now (not breathing, choking, a fall, chest pain, stroke signs); if so, keep them safe and get the nurse at once.
Ask whether the task is within the nursing assistant’s scope and training; if not, decline politely and tell the nurse.
Respect the resident’s rights: privacy, choice, refusal of care, dignity and freedom from abuse and unneeded restraints.
Apply the basic rules: hand hygiene, body mechanics, bed low and call light within reach, weak side first when dressing.
Observe and report: compare with the resident’s usual state and report changes promptly and objectively.
Nursing math & unit conversions
Metric steps
1 kg = 1000 g, 1 g = 1000 mg, 1 mg = 1000 mcg, 1 L = 1000 mL
Weight and length
1 kg = 2.2 lb, 1 lb = 16 oz, 1 in = 2.54 cm, 1 ft = 12 in
Household measures
1 tsp = 5 mL, 1 tbsp = 15 mL, 1 fl oz = 30 mL, 1 cup = 8 fl oz = 240 mL
Write the given quantity with its unit and the unit you want.
Pick the equivalent: 1000 between kg, g, mg and mcg or L and mL; 1 kg = 2.2 lb; 1 tsp = 5 mL, 1 tbsp = 15 mL, 1 fl oz = 30 mL, 1 cup = 240 mL.
Write it as a fraction so that the unwanted unit cancels; for a rate, use one fraction per unit that changes.
Check the direction: a smaller unit gives a bigger number.
Round only the final answer, to the precision the question names.
2Practice problems
1.Nursing assistant (CNA) knowledgeMedium
How is a clean-catch (midstream) urine specimen collected?
ACollect urine from a bedpan that has toilet paper in it
BPour urine from the catheter drainage bag into the container
CCollect the very first urine of the day straight into the sterile container
DClean the area, start urinating, then catch the middle of the stream
2.Nursing assistant (CNA) knowledgeHard
A resident's dentures are missing after lunch. What should the nursing assistant do first?
AWait until the next day to see if they turn up
BGive her another resident's spare dentures
CTell the resident that she will have to pay for new ones
DSearch the tray, napkins and linen, and report the loss
3.Nursing math & unit conversionsMedium
Practice exercise (made-up values, not clinical guidance). A dose calculation for an injection gives 11.1913 mL. The rule in this exercise is that volumes of 1 mL or more are rounded to the nearest tenth of a mL. What value x do you record?
11.1913 mL
x = mL
4.Nursing math & unit conversionsHard
Practice exercise (made-up values, not clinical guidance). A blood glucose result is 17 mmol/L. Using 1 mmol/L = 18 mg/dL for glucose, find c in mg/dL to the nearest whole number.
17 mmol/L1 mmol/L = 18 mg/dL
c = mg/dL
3Solutions
1.Nursing assistant (CNA) knowledge
Answer: D · Clean the area, start urinating, then catch the middle of the stream
Why this is the answer
After cleaning the area, the resident starts to urinate, then urine is caught midstream in a sterile container without touching its inside. The container is labeled and handled as the nurse directs.
Answer
D · Clean the area, start urinating, then catch the middle of the stream
2.Nursing assistant (CNA) knowledge
Answer: D · Search the tray, napkins and linen, and report the loss
Why this is the answer
Missing dentures are often wrapped in napkins and sent away with trays or linen. A prompt search and report give the best chance of finding them, and the loss is documented according to policy.
Answer
D · Search the tray, napkins and linen, and report the loss
3.Nursing math & unit conversions
Answer: x = 11.2 mL
Rounding: look at the digit just after the place you round to: 5 or more rounds up, 4 or less leaves the digit as it is. Round only the final answer, never the steps. Typical exam rules: volumes of 1 mL or more to the nearest tenth, volumes below 1 mL to the nearest hundredth, drip rates to whole drops and weights to one decimal place; always follow the rule the question states.
Digit in the tenths place
11.1913 → 1
Only the next digit decides
11.1913 → 9
9 is 5 or more, so round 1 up.
The digits after it (13) are ignored: round once, never step by step.
Round
x = 11.2 mL
Answer
x = 11.2 mL
4.Nursing math & unit conversions
Answer: c = 306 mg/dL
Dimensional analysis: write the given quantity, then multiply by conversion factors written as fractions (for example 60 min/1 h or 1 mg/1000 mcg) so that each unwanted unit appears once on top and once underneath and cancels. When only the wanted unit is left, calculate. Use the equivalents the question gives and round only the final answer.