


DecimalsRounding DecimalsRounding is frequently used to give an estimate of a given number. For example, the balance of a savings account shows the amount to the nearest cents. But when the number is big, such as in a govenment's budget, we may estimate the amount by rounding it to the nearest millions or even billions of dollars. Let us call the digit at the place value you are interested in the rounding digit.
(I) Rounding a whole number: If the rounding digit is at the ones position, then there is nothing to do. Otherwise, look at the digit just to rthe right of it.
Example 1Round the given number to the place value indicated.
Exercise 1Round the given number to the place value indicated.
(II) Rounding a decimal number: If the rounding digit lies to the left of a decimal point, then drop all digits after the decimal point and proceed as in (I). Otherwise, look at the digit just to the right of the rounding digit.
Example 2Round the given number to the place value indicated.
Exercise 2Round the given number to the place value indicated.
Note: If the number represents a sum of money, then
For example, $100.486 to the nearest cents is $100.49 and to the nearest dollars is $100.
It is easier to say, and therefore more common to say, "round to one, two, three etc decimal places (d.p.)" than "round to the nearest 10ths, 100ths, 1000ths etc".
Exercise 3Round the given number to the number of decimal places indicated.
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