When solving a problem, the final answer should be rounded to a reasonable degree of accuracy based on the context of the question. This means the answer should be precise enough to be useful, but not so precise that it suggests unrealistic accuracy.

A sensible approach is to match the accuracy of the values given in the question. If numbers are given to a certain number of decimal places or significant figures, the final answer should usually be rounded to a similar level.

For example, if a length is measured as \( 12.4 \) cm, it is only accurate to one decimal place. If another value is \( 3.2 \), that is also given to one decimal place. The final answer should not be given to more accuracy than this.

Worked example

$$
12.4 \times 3.2 = 39.68
$$

A reasonable final answer, rounded to one decimal place, is:

$$
39.7
$$

In different contexts, the appropriate rounding can change. Money is usually rounded to two decimal places. Numbers of people are rounded to the nearest whole number because fractions of a person are not meaningful.

Always consider the context of the problem and the accuracy of the given values before deciding how to round your final answer.

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