Now that we’ve covered *scientific*, *engineering*, and *decimal notation*, it’s time to learn the **rules of significant figures **(abbreviated **SF**, and also referred to as *significant digits*). Without knowing these rules, you will NOT be able to **add**, **subtract**, **multiply**, or **divide** any number correctly moving forward. The first video will walk you through how to count for the correct number of significant digits in any type of number:

Next, you’ll need to know the rules for **rounding** numbers to the correct number of significant figures. **Rounding** and** significant figures** go hand-in-hand in almost every calculation. When you’re asked to calculate something to the correct number of SF’s, it implies that you round as well. Also, don’t assume you know the rules, because what you learned in elementary school no longer applies here the same way, especially when your last significant figure is a 5.

Now that you now the rules of counting and rounding SF’s, let’s trying **adding**, **subtracting**, **multiplying**, or **dividing **numbers.

**Part 2** of this series shows more of the same, except we extend our understanding to numbers of greater complexity, such as the operations applied to scientific notation numbers.

A few things to keep in mind when operating with numbers in scientific notation are summarized underneath. Of course, most scientific calculators – namely the one recommended for this course – enables you to find the answer without the recommendations below.

Tips for Adding and Subtracting Scientific NumbersIf two or more numbers to be added or subtracted have the

samepower of 10, we combine the numbers and keep the same power of 10. For example: nullIf the powers of 10 are different, they

must be made equalbefore the numbers can be combined.

- A shift of the decimal point of one place to the left will increase the exponent by 1.
- A shift of the decimal point of one place to the right will decrease the exponent by 1.
For example:

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