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Rounding, Significant Figures & Bounds
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
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Mathematics · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
To round 4.783 to 2 decimal places, the next digit is 3, so we keep 4.78. Rounding always loses a little accuracy.
In 0.004582 the first significant figure is 4. To 2 s.f. it rounds to 0.0046. Significant figures show how precise a measurement is.
A length given as 45 m (to the nearest metre) could really be anywhere from 44.5 m up to (but not including) 45.5 m. Those are its lower and upper bounds.
Max sum uses both upper bounds. Max quotient a÷b uses UB(a)÷LB(b), because dividing by a smaller number gives a bigger result.
Hard words & meanings
| round | to replace a number with a simpler nearby value to a stated accuracy |
| decimal place | a digit position after the decimal point |
| significant figure | a digit that carries meaning about a number's precision, counted from the first non-zero digit |
| leading zero | a zero before the first non-zero digit; it only holds place and is not significant |
| lower bound | the smallest value that still rounds to the given number; it is included |
| upper bound | the smallest value that rounds up to the next number; it is excluded |
| error interval | the range of possible true values, written LB ≤ x < UB |
| degree of accuracy | the unit a value has been rounded to, such as nearest cm or 1 d.p. |
Model exam answers, grammar & audio
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