How to Round Numbers and Decimals

Description

This is a basic video tutorial on rounding numbers to the nearest 10, 100, and 1000. Many example problems are provided in this video.

Overview

Rounding is a very basic concept in math, but is used just as much in higher level math as in the basic classes. It is used a lot with statistics to make the information much easier to use. The basic rule of rounding is that any number 5 or over gets rounded up, and any number 4 or lower gets rounded down. This is very easy if you have to round to the nearest 10 – just round down or up accordingly. But what about rounding decimals? Decimals have the same basic principle for rounding, but can be difficult because you’re working backwards to eliminate something, not change something you already have. Let’s say you are given this decimal: 0.385630483. You want to round this down to three decimal places. So you take the very last number – 3. 3 falls in the category of 4 or lower, so the number after it does not get changed. So you can get rid of the 3. Now, look at the next number. The next number is an 8. 8 falls in the category of 5 or higher, so the number after it gets rounded up. The number after the 8 was a 4. When you get rid of the 8, you must change the 4 into a 5. So now, you look at the 5. The 5 is also in the category of 5 or above, so your next number, which was a 0, gets changed to 1. If you keep following this pattern all the way down the decimal line, your new decimal will be 0.386.