This key facts covers Key Terminology within Bounds & Error Intervals for GCSE Mathematics. Revise Bounds & Error Intervals in Number for GCSE Mathematics with 14 exam-style questions and 5 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 2 of 7 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Key Terminology
| Term | Meaning | Example (8.3 to 1 d.p.) |
|---|---|---|
| Lower Bound (LB) | Smallest value that rounds to the given value | 8.25 |
| Upper Bound (UB) | Smallest value that would round UP | 8.35 |
| Error Interval | Range written as inequality | 8.25 ≤ x < 8.35 |
Note: Lower bound uses ≤ (could be exactly this), Upper bound uses < (never reaches this)
Practice questions for Bounds & Error Intervals
A length is 240 cm to the nearest 10 cm. What is the lower bound of the length?
A mass m is 45 kg to the nearest kilogram. Write down the error interval for m using inequality notation.
Quick recall flashcards
Rationalising
Remove surd from denominator: 1/√2 = √2/2
Max of A ÷ B
Max = UB(A) ÷ LB(B). Big top, small bottom = big answer