Fractions Trivia
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40 free Fractions trivia questions with answers — trivia quiz, new questions added Aug 2026.
Fractions are the first piece of maths most people remember finding hard, and the last one they keep using: halving a recipe, reading a tape measure, working out what a sale really costs. They also hide some of the best stories in arithmetic, from a hamburger that flopped because customers misread a fraction to a stock market that priced shares the way pirates split coins. These 40 questions mix worked problems with the ideas behind them: equivalent fractions and lowest terms, adding and subtracting over a common denominator, multiplication and division, converting between fractions, decimals and percentages, and comparing and ordering. Alongside them sit the vocabulary of fraction notation and the history of who wrote fractions how, from ancient scribes to the booklet that sold Europe on decimals. It suits a maths classroom starter, a revision session before a test, or a pub-quiz round where everyone thinks they know the answer and half the room gets it wrong.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Which patty size did A&W pitch against McDonald's Quarter Pounder, only for focus groups to judge it smaller?
1/3 lb
1/3 lb: the Third Pounder won taste tests, but A&W's owner later wrote that focus groups saw the 3 in 1/3, took it for less meat than the 4 in 1/4, and thought they were being overcharged.
Q 02What share of an 18-karat gold ring is actually gold, on a scale where 24 karat means pure?
75%
18-karat gold is 75% gold, because karats count parts per 24 and 18/24 reduces to three quarters. The rest is copper, silver or other metals that make the ring harder.
Q 03In which fraction of a dollar did the NYSE quote prices until 1997, a habit from Spanish coins chopped into 'bits'?
Eighths
Eighths: Spanish dollars were chopped into eight 'bits' to make change, which is why a quarter is still 'two bits', and Wall Street kept its 1/8 tick until sixteenths arrived in 1997 and cents in 2001.
Q 04What does a '2×4' board actually measure once it has been dried and planed?
1 1/2 × 3 1/2 in
1 1/2 × 3 1/2 in: the name once described the rough-sawn board, before planing and drying trimmed it, and today's mills cut it under the nominal size from the start.
Q 05Which Roman punishment killed every tenth man of a unit that had shown cowardice?
Decimation
Decimation: in Polybius's account the victims were picked by lot and beaten to death by their own comrades, while the survivors were put on barley rations and made to camp outside the defences.
Q 06Which church levy took one part in ten of a farmer's produce?
Tithe
Tithe: it is simply the Old English word for 'tenth', which the church kept using after 'tenth' replaced it in everyday counting, and the dime takes its name from the same idea by way of French.
Q 07Which graphic, first drawn by William Playfair in 1801, shows fractions of a whole?
Pie chart
Pie chart: Florence Nightingale later reshaped it into her 'rose' diagram to show how poor sanitation was killing soldiers in the Crimean War, and the French know it as a camembert.
Q 08What do British musicians call the note Americans know as a quarter note, worth a quarter of a semibreve?
Crotchet
Crotchet: the name is Old French for 'little hook', from the hooked shape the note had in medieval notation, though today's crotchet is a plain stem and the hooks belong to quavers.
Q 09What fraction of an hour is a 15-minute coffee break plus a 10-minute one, the sum 1/4 + 1/6?
5/12
5/12: quarters and sixths first line up as twelfths, 3/12 + 2/12, and the clock agrees, since 15 + 10 minutes is 25 of the 60.
Q 10Which name does 2 1/2 go by, the form tape measures and recipes prefer to the top-heavy 5/2?
Mixed number
Mixed number: it hides a plus sign, since 2 1/2 means 2 + 1/2, the opposite of algebra, where writing two things side by side means multiplying them.
Q 11What is 5/3 called in relation to 3/5, since the two multiply to exactly 1?
Reciprocal
The reciprocal flips a fraction over, and dividing by a fraction means you multiply by it instead: 5/3 × 3/5 = 1, so dividing by 3/5 is the same as scaling up by 5/3.
Q 12What is 5/6 − 1/4, the difference found by rewriting both fractions over the common denominator 12?
7/12
5/6 − 1/4 = 7/12, since 5/6 is 10/12 and 1/4 is 3/12, and 10 − 3 = 7. Subtracting tops and bottoms separately would give the nonsense answer 4/2.
Q 13What is 4/5 × 5/6, the product that simplifies the moment the two fives cancel each other?
2/3
2/3: going straight across gives 20/30, but cancelling the matching fives first leaves 4/6, and halving both parts finishes the job.
Q 21How many 1/8-cup scoops of flour fill a 5/8-cup measure, a division done by flipping the divisor to multiply instead?
5
Five scoops, because 5/8 ÷ 1/8 = 5/8 × 8/1 = 40/8 = 5, since both amounts are counted in the same size of slice.
Q 22Which of these denominators gives a decimal that stops rather than repeats, having no prime factor other than 2 and 5?
16
16: a fraction in lowest terms gives a decimal that stops only when its bottom divides a power of ten, and 10 is just 2 × 5, so 1/16 ends at 0.0625 while 1/12 runs on as 0.08333…
Q 23Which shortcut tests whether 3/4 and 9/12 are equal by checking that 3 × 12 matches 4 × 9?
Cross-multiplying
Cross-multiplying: it is shorthand for multiplying both fractions by both bottoms, 4 × 12, which leaves 3 × 12 on one side and 9 × 4 on the other, and both come to 36.
Q 14Which unit, written like a % sign with an extra zero on the bottom, often expresses seawater salinity?
Per mille
Per mille: it counts parts in a thousand, yet oceanographers' practical salinity scale of 1978 works from how well seawater conducts electricity and gives a plain figure with no unit at all.
Q 15Which mathematician's 1585 booklet De Thiende told surveyors and tradesmen to calculate in decimal fractions?
Simon Stevin
Simon Stevin's De Thiende ('The Tenth') won Europe over to decimal fractions, though he did not invent them: al-Uqlidisi had used them in a book written in Damascus in 952.
Q 16Which Italian mathematician, taught arithmetic in North Africa as a boy, wrote fractions with the bar a Moroccan scholar had introduced?
Fibonacci
Fibonacci: his father acted for Pisa's merchants at the customs house in Bugia, in today's Algeria, and had the boy schooled there, and his Liber Abaci used the fraction bar first attested in al-Hassar's work.
Q 17What fraction of a Roman pound was the uncia, a unit whose name survives in both the ounce and the inch?
One-twelfth
One-twelfth: Romans counted fractions in twelfths, so the uncia was a twelfth of their foot as well as their pound, and the inch still is one, though the everyday ounce is now a sixteenth of a pound.
Q 18What is the bar over the repeating digits of a decimal like 0.1666… called, from the Latin for 'bond' or 'tie'?
Vinculum
Vinculum: the same horizontal 'tie' was once drawn over groups of terms to bind them together, a job parentheses mostly do today, and it survives as the roof of the square-root sign.
Q 19Which formal name for the slash in 3/4 recalls the mark's old use as the shilling mark in British prices?
Solidus
Solidus: it was a Roman gold coin whose name became the 's' for shillings, and the stroke in a price like 7/6 is said to be a stretched long s.
Q 20What do older textbooks call the ÷ symbol, a word that also names a dagger mark flagging dubious lines in manuscripts?
Obelus
Obelus: ancient editors set the mark beside lines they thought spurious, and ÷ had stood for subtraction before a Swiss algebra book of 1659 turned it into the division sign.
Q 24What are fractions like 11/32, with a power of two on the bottom, called, the kind an inch ruler marks?
Dyadic
Dyadic: a computer's binary floating-point numbers are all fractions of this kind, which is why it can store 3/8 exactly but only approximate 1/10.
Q 25Which camera setting is written as a fraction like f/8, the lens's focal length divided by eight?
Aperture
Aperture: f/8 means the opening is one-eighth of the focal length across, so a bigger f-number is a smaller hole, and f/16 lets in a quarter of the light of f/8.
Q 26Which of these fractions is equal to 3/5, found by scaling top and bottom by the same factor?
9/15
9/15 is 3/5 with both parts tripled, and scaling top and bottom alike never changes a fraction's value, which is why 6/15, with only the top doubled, is a different amount.
Q 27What is 28/36 in lowest terms, the form reached once top and bottom are both divided by 4?
7/9
28/36 reduces to 7/9 because 4 divides both 28 and 36 and no larger factor does, so 7/9 cannot be simplified any further.
Q 28What is 7/8 as a decimal, the figure reached by adding three steps of 0.125 to 0.5?
0.875
7/8 = 0.875, since 1/8 is 0.125 and seven of them make 0.875, which is exactly what dividing 7 by 8 on a calculator shows.
Q 29A recipe's 3/4 cup of butter is cut to half for a small batch; how much butter goes in?
3/8 cup
3/8 cup: halving a fraction doubles its bottom, so 3/4 × 1/2 = 3/8, while doubling the top instead would give 6/4, twice the butter.
Q 30What percentage is 7 right answers out of 20, the fraction 7/20 scaled up to a denominator of 100?
35%
7 out of 20 is 35%, because scaling top and bottom by 5 gives 35/100, and 'per cent' literally means 'per hundred'.