Rounding is done to make a number simpler to handle while keeping it close to its original value. Rounding is often used to help you estimate when adding a group of numbers. When you are working with simple numbers, rounding is much easier.
Say your friends all want to order pizza and you need to know about how much each person will need to chip in. You can simply round the price of each pizza instead of adding each one individually. Rounding can help you make sure Joe pays his part of the bill without getting out your calculator.
There are two general rules for rounding:
- If the number you need to round is followed by a 5,6,7,8, or 9, you will need to round up to the next number.
- If the number you are rounding is followed by a 0,1,2,3, or 4, you will need to round down to the next number.
Numbers can be rounded to the nearest tenth, hundredth, thousandth, etc. It is important to know which place you are rounding so you do not make a mistake in the process.
It is also important to first understand place value so you can know where the number you need to round is located.
Let’s say you are attempting to round the number 5,875.
If you are asked to round this to the nearest tenth, your answer would be 5,880.
If you are asked to round this to the nearest hundredth, your answer would be 5,900.
If you are asked to round this to the nearest thousandth, your answer would be 6,000.
Once you have rounded the number you were asked to round, you will simply make all the numbers to its right become zeros. This is important to remember or your answer will not be correct.
Learning to round can be especially helpful if your mom sends you to the store to pick up a few items and you want to make sure you have not gone over the amount of money she gave you. Let’s say you purchase these items:
Tomatoes $1.89
Soda $.99
Milk $3.68
Coffee $2.56
Your mom has only given you $11.00 and you sure don’t want to spend your own money you are saving for that video game, so you round each of these amounts to the nearest dollar and quickly add them to see if you will have enough money.
When rounded, the amounts look like this:
Tomatoes $2.00
Soda $1.00
Milk $4.00
Coffee $3.00
When you add these amounts together, you come up with $10.00. Looks like you won’t be pulling any money from your video game fund because you will have enough money to pay from your mom’s cash.
Rounding is one of those math skills you will definitely end up using long after you leave school, so it is important to master this helpful skill now.
Once you start practicing rounding, it will become like second nature to you. If you remember the rounding rules above, you should have no problems.