Rounding

Round down numbers with digits less than ‘5’ and round up numbers with digits ‘5’ or greater.

Example: 7.3 would be rounded down to 7.0 or 7; but 7.7 would be rounded up to 8.

You can round off the number to fewer digits following these rules for rounding off:

* Determine how many digits (numbers) you want in the answer.

* Look at the next number (the number after those digits). If it is less than 5, drop all remaining numbers.

* If the number is 5 or more, make the preceding number one unit greater, then drop all remaining numbers.

Example: If we want to round off 1.5263792 inches to two digits, we look at the third number. Since that number (2) is less than 5, drop it and all remaining numbers and end up with 1.5 inches.

Round off 1.5263792 inches to three digits, look at the fourth number. Since the fourth number (6) is more than 5, make the preceding number one unit larger, then drop the remaining numbers, leaving 1.53 inches.

NOTE: When working problems, always wait until you get the final answer before rounding off.

Review:

1. How many feet in 30 inches?

2. How many cubic feet (ft3) in one cubic yard (yd3)?

3. Convert flow of 1 cuft ft/second to gallons/minute.

4. Convert flow of 1 gallon/minute to gallon/day.

5. 1 gallon of water weighs 8.34 pound and 1 cubic foot of water weighs 62.4 pounds, how many gallons are in 1 cubic foot of water?

Answers:

1. (30 inches) / (1 foot/12 inches) = (30) / (12) = 2.5 feet

2. (1 yd3)=(3 ft/ 1 yrd) X (3 ft/ 1 yrd) X (3 ft/ 1 yrd) = 27 ft3 or 27 cuft

Notice the three /yrd (in each 3 ft/ 1 yrd) cancel out due to the yd3 (in the 1 yd3) leaving only the three ft on top which translates to cuft

3. (1 cuft/1 sec) X (7.48 gal/1 cuft) X (60 sec/1 min) = (7.48 X 60) = 448.8 gal/min rounded to

449 gal/min

4. (1 gal/min) X (60 min/hr) X (24 hr/day) = (60 X 24) = 1440 gal/day

5. (1 gal/8.34 lbs) X (62.4 lbs/1 cuft) = (62.4) / (8.34) = 7.48 gal/cuft