4,984000 people-estimated=it is not possible for them to count the amount of all the people in the whole of singapore.
$257 billion-estimated=it is written as a gross amount which meant that the $257 billion was estimated
682.7 sq km-estimated=it is impossible that they are able to measure the exact area of singapore.
percentage of races-estimated=it is not possible because they can't possibly count every single person's religion one by one
height of bukit timah hill(163.36m)-estimated=the height of the hill might have had more than two decimal places in measurement so it is an estimated figure