If someone says they're "180 cm tall" (to nearest cm), they could actually be anywhere from 179.5 cm to 180.5 cm! When a value is rounded, there's always a hidden range of possible values - that's what bounds are about. This matters in engineering where precision is critical.
This introduction covers The Hidden Range 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 1 of 7 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
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
Max of A ÷ B
Max = UB(A) ÷ LB(B). Big top, small bottom = big answer
Rationalising
Remove surd from denominator: 1/√2 = √2/2