How do know when you need an exact answer?

What is the percent of 4 over 6? What is the area of a pan measuring 12 inches by 9 inches? What is the perimeter of a square whose sides is 18meter? What number is when you add all of its factors the sum is 12? How does the decimal move from kolometers to meters? How did the Aztec know which days were lucky and which were not? What is half of 14760? What is 1499 plus 999? What is the length of the missing leg of a right triangle whose hypotenuse has measure 5cm and whose other leg measures 11cm? What is the remainder when 100 is divided by 11? 0.627 as a percent? What does R5.99 mean? Which compound conditional statement involves the inclusive or? Is there rain on any day is there rain on any day of the week? How is 4 less a number written in an algebraic expression? How do you write the number 1245 in scientific notation format? What time is the first hour of the day? Is 0.5714 a rational number? In a set of observations which measure of central tendency reports the value that occurs most often? How do you do skewed to the left?

How do know when you need an exact answer?