Six tools, six number skills
These are not six versions of the same drill. The Mental Math Drill covers the four operations across a mixed range, which is the closest thing here to general fluency. The Multiplication Quiz narrows to the times tables, where the whole problem turns out to be roughly a dozen facts once you strip out the ones that follow visible rules.
The Percentage Quiz is a different skill entirely — proportional reasoning, the thing you actually use for a discount, a tip or an interest rate — and it depends on building answers from a few anchors rather than on recall. Roman Numerals is not arithmetic at all but notation: reading a number system that adds left to right except when it subtracts.
The Fraction Quiz and the Unit Conversion Quiz cover the two topics that most often go wrong once the times tables are secure. Fractions fail when they are treated as two separate whole numbers; conversions fail when a decimal point moves the wrong way. Both quizzes build their wrong options from exactly those mistakes.
Where to start
- Helping someone learn their tables: the Multiplication Quiz, and track which questions go wrong rather than the total score.
- Wanting something useful in daily life: the Percentage Quiz. It is the one whose skill you will use this week.
- Just warming up: the Mental Math Drill on a short duration with one operation selected.
- Stuck on fractions at school: the Fraction Quiz, which shows the working whenever you pick a wrong answer.
- Shopping abroad or reading a US recipe: the Unit Conversion Quiz, from inches and pounds to Fahrenheit.
- Reading a clock face, a film date or a Super Bowl number: Roman Numerals, which converts both directions and has a quiz below it.
- Practising with a class: all six work projected on a screen, need no accounts and reset instantly for the next round.
Why mental arithmetic still earns its place
The argument against practising arithmetic is that everyone carries a calculator, and it misses what the skill is actually for. Fluency with small numbers is what lets you notice that a total is wrong, that a discount is worse than it looks, or that an answer is off by a factor of ten — none of which a calculator will tell you, because it will confidently return whatever you typed.
There is a second effect worth knowing. Any step you have to compute occupies working memory that could hold the actual problem, so being fluent with the small pieces makes larger problems feel easier rather than merely faster. That is the real reason times tables are taught to the point of automaticity.
Frequently asked questions
How long should I practice each day?
Five to ten minutes of focused drills beats an occasional long session — fluency comes from frequent short repetition.
Can I choose the difficulty?
Yes — each tool has its own settings: number ranges and operations in the drill, specific tables in the multiplication quiz, timer length in the percentage quiz.
Are these suitable for beginners?
Yes — every quiz starts gentle and lets you narrow the range, so learners at any level can find a comfortable starting point.
Why practice mental math when every phone has a calculator?
Because most real calculations happen where you'd never open a calculator: judging a discount at the shelf, splitting a bill, sanity-checking a quote. Fluent mental math also catches typing mistakes — you notice when a calculator answer is off by a factor of ten because you already know roughly what it should be.
What's the fastest way to master the times tables?
Drill one table at a time until it feels automatic, then mix it with the ones you already know — the multiplication quiz lets you select exactly which tables appear. Give extra rounds to the 6, 7 and 8 tables, where most errors live, and keep sessions short but daily.
How can I calculate percentages faster in my head?
Build everything from 10%: shift the decimal once (10% of 240 is 24), halve it for 5%, double it for 20%, add combinations for the rest — 35% is three tens plus a five. Another trick: x% of y equals y% of x, so 8% of 50 is just 50% of 8. The percentage quiz drills exactly these moves.