Cambridge questions are written in precise mathematical English. If you know exactly what product, difference, justify and estimate ask you to do, you will not lose marks answering the wrong question.
| Term | What it means | Example |
|---|---|---|
| expression | A collection of numbers and letters with no equals sign. | 5n + 4 is an expression. |
| equation | Numbers and letters together with an equals sign. | 5n + 4 = 19 is an equation. |
| term | One part of an expression, separated by + or −. | 5n + 4 has two terms: 5n and 4. |
| like terms | Terms with exactly the same letters to the same powers. | 5a and 2a are like terms; 5a and 2b are not. |
| collecting like terms | Adding or subtracting like terms to shorten an expression. | 3x + 2x = 5x. |
| simplify | To write an expression in as short a form as possible. | 4x + 3y + 2x − y simplifies to 6x + 2y. |
| coefficient | The number that multiplies a variable. | In 5n the coefficient of n is 5. |
| constant | A number on its own, whose value never changes. | In 5n + 4 the constant is 4. |
| variable | A letter representing a quantity that can change. | In A = lw, both l and w are variables. |
| unknown | A letter standing for a number you do not yet know. | In x + 5 = 12, x is the unknown. |
| equivalent expression | An expression with the same value as another. | 5 × n + 4 and 5n + 4 are equivalent. |
| formula | A rule showing the relationship between quantities. | A = l × w is the formula for the area of a rectangle. |
| formulae | The plural of formula. | A = lw and P = 2(l + w) are two formulae. |
| substitute | To replace a letter with a number. | Substituting x = 4 into 3x + 2 gives 14. |
| derive | To write your own formula from a situation. | From “$8 a book” you derive C = 8n. |
| expand | To multiply out brackets and write the expression without them. | 4(n + 3) expands to 4n + 12. |
| brackets | Symbols ( ) used to group terms together. | In 2(x − 5) the brackets show that both terms are multiplied by 2. |
| solve | To find the value of the unknown that makes an equation true. | Solving x + 5 = 12 gives x = 7. |
| solution | The value of the unknown that makes the equation true. | The solution of 2y + 4 = 16 is y = 6. |
| inverse operation | The operation that undoes another one. | You undo “+ 5” by subtracting 5. |
| inequality | A statement that one quantity is greater or less than another. | x > 5 is an inequality. |
| integer | A positive or negative whole number, including zero. | The smallest integer with x > 5 is 6. |
| index | The small raised number showing a power. | In a² the index is 2. |
| simplest form | An expression that cannot be shortened any further. | 6x + 2y is the simplest form of 4x + 3y + 2x − y. |