Practise the formulas

Pick the formulas and how many questions of each. Every answer is marked on the spot, and when one goes wrong you can open the working — step by step, with the numbers you were just given.

Pick formulas

20 questions

How the questions are written

What the choice does

With the formula in front of you, the questions test whether you can substitute into it. Without it they test whether you know it. The working always shows it, so you are never stuck.

With names the questions write out what each quantity is called — Base instead of b — and you have to work out which letter in the formula the word belongs to. With names and letters the letter follows in brackets, Base (b), so that link is given.

Which stage

646 of 646 formulas

Arithmetic

20 questions

Percentage of a numbera=bp100
Percentage changep=b−aa·100
Change factorb=af
Successive percentage changep=p₁+p₂+p₁p₂100
Sale price after a discounts=p−pd100
Scaleb=as
Product of powersa^maⁿ=a^m+n
Quotient of powersa^maⁿ=a^m−n
Power of a power(a^m)ⁿ=a^mn
Power of a producta^xb^x=(ab)^x
Power of a quotienta^xb^x=(ab)^x
Zero exponenta⁰=1
Negative exponenta⁻ⁿ=1aⁿ
Root of a productab=ab
Root of a quotientab=ab
Fractional exponentx^mn=ⁿx^m
Power equationxⁿ=a
Adding fractionsab+cd=ad+cbbd
Subtracting fractionsab−cd=ad−cbbd
Multiplying fractionsab·cd=acbd
Dividing fractionsabcd=adbc
Mixed numbersa+bc=ac+bc
Fraction to decimald=ab
Fraction to percentagep=100·ab
Direct proportiony=kx
Inverse proportiony=kx
Cross multiplicationad=bc
Share of a ratioS=Taa+b
Percentage pointsΔp=p₂−p₁
Index numberI=100·xx₀
Scientific notationx=a·10ⁿ
Greatest common divisorgcd(a, b)=gcd(b, amodb)
Least common multiplelcm(a, b)=abgcd(a, b)
Product of the GCD and the LCMgcd(a, b) lcm(a, b)=ab
Congruence and modular arithmeticamodn=a−n⌊an⌋
Absolute valuea=|x|
Absolute value, the definition|x|=x,x≥0−x,x<0
Proportional to the squarey=kx²
Inversely proportional to the squarey=kx²

Algebra

Geometry

Trigonometry

Functions and graphs

Straight lines

Polynomials

Exponential change

Indices and series

Calculus

Statistics and probability

Motion

Mechanics

Electricity

Thermodynamics

Waves and optics

Modern physics

Stoichiometry

Solutions and concentration

Gas laws

Acids and bases

Interest

Borrowing and repayment

Business

Tax and VAT

Household

The body

Which set

What the choice does

The link in the address bar holds your choice. Share it and everyone gets exactly the same questions — save it and you get them back next time.

Fetching the questions …

Questions in several steps

Questions where the answer to one step is one of the numbers in the next.

12 questions

Go to the questions in several steps

Reading graphs and charts

Questions about a drawn chart or graph.

10 questions

Go to the graph and chart questions

Algebra methods

Rational expressions, root equations, intervals and linear programming, with the solution in steps.

12 kinds of question

To the algebra methods

Nothing is stored and nothing is added up: the site has no accounts, and it cannot show anyone else what you answered. If you want the same questions on paper they are a printable worksheet with an answer key, and every formula has a page of its own that solves in whichever direction you need.

For teachers: make a worksheet to print Ready-made worksheets with answer keys All formulas