Can the numbers on a label be taken as what you eat?

No. Labels are usually per 100 g or per serving, so multiply by the servings you really eat.

Why are antibiotics not always needed for a cold?

Most colds are viral and antibiotics only work on bacteria, while misuse breeds resistant strains.

Primary General Studies, Healthy Living, Paper 4: water, eye care and label maths

2026-10-31

Tutor Prep Guide · Primary General Studies

Ten items on daily water, brushing time, the 20-20-20 rule, the three main nutrients, fat per packet, sugar in a can, calorie percentage, pulse drop, height from BMI and antibiotics.

Focus　About 6 to 8 cups of water a day; brush for at least 2 minutes; every 20 minutes look 20 feet away for 20 seconds; carbohydrates, protein and fat are the three nutrients; scale labels to real portions; percentage is part over whole; a drop uses the starting value; height is the square root of mass over BMI; antibiotics do not work on viruses.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	25
Difficulty mix	Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1
Chapter	Chapter: Primary General Studies: Healthy Living
Level	P4 to P6

02　Questions (10 items)

FoundationHow much water is usually recommended each day, counted in 250 mL cups?
FoundationHow long should you brush your teeth each time?
FoundationWhat is the 20-20-20 rule for eye care during long reading or screen time?
FoundationWhat are the three main nutrients in food?
IntermediateA 250 g packet of biscuits has 20 g of fat per 100 g. How much fat is in the whole packet?
IntermediateThe daily sugar limit is about 50 g. A 330 mL can of soft drink has 10.6 g of sugar per 100 mL. How much sugar is in one can?
IntermediateA 12-year-old needs about 2 000 kcal a day and eats 500 kcal at breakfast. What percentage of the daily need is that?
ChallengeAfter running, a pulse of 150 beats per minute falls to 90 after ten minutes of rest. What is the percentage drop?
ChallengeAn adult has a mass of 60 kg and a BMI of 24. What is the approximate height?
Error redoA classmate says antibiotics should be taken at once for a cold with fever to recover faster. Is this correct?

03　Answers and one-line notes

#	Answer	One-line note
1	About 1.5 to 2 litres, which is roughly 6 to 8 cups.	You need more after exercise or in hot weather, and dark urine is a sign to drink more.
2	At least 2 minutes, twice a day.	Brushing too briefly leaves plaque behind and raises the risk of decay and gum disease.
3	Every 20 minutes, look at something 20 feet away for 20 seconds.	Looking far away relaxes the eye muscles and reduces strain and short-sightedness.
4	Carbohydrates, protein and fat.	Carbohydrates give energy, protein repairs the body, and fat stores energy and keeps you warm.
5	50 g.	Work out the amount per gram then multiply: 20 divided by 100, times 250, is 50 g.
6	34.98 g, which is about 35 g.	The label is per 100 mL, so scale it to the can: 10.6 divided by 100, times 330, is 34.98 g.
7	It is 25 per cent.	Percentage is part over whole times 100: 500 over 2 000 is 25 per cent.
8	It drops by 40 per cent.	The drop is the fall over the starting value: 150 minus 90, divided by 150, is 40 per cent.
9	About 1.58 m.	BMI is mass over height squared, so the height is the square root of 60 over 24, about 1.58 m.
10	No. Colds are usually caused by viruses, and antibiotics only work on bacteria.	Misusing antibiotics breeds resistant bacteria, so the drugs fail when they are really needed.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

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