06 – Upper and lower bounds (UB, LB)

If a value has been rounded, it is useful to know what possible values the exact value could have been.


Example:

 

An estimate of my height is 176 cm to the nearest cm. That means it could be any height from 175.5 cm to 176.5cm and these are called the lower and upper bounds.

The lower bound is the smallest value that would round up to the estimated value.

The upper bound is the smallest value that would round up to the next estimated value.

To calculate the upper and lower bounds half the degree of accuracy specified then add this to the rounded value for the upper bound and subtract it from the rounded value for the lower bound.
In my example, half the accuracy of 1cm is 0.5cm, so 0.5cm was added and subtracted to/from 176cm


Your turn:

 

Find UB and LB of 10.12 seconds, to 2 dp

Enter your answer here:
≤ 10.12 <

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