# How can I perform the following operation 32500 + 26 823 - 56 000 taking into account the number of significant figures?

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I know that the correct answer is 3 300 or 3.3 x 10^3, but I do not understand why.

Please clarify? Thanks!

I know that the correct answer is 3 300 or 3.3 x 10^3, but I do not understand why.

Please clarify? Thanks!

##### 1 Answer

Here's how you can do that.

#### Explanation:

The first thing to note here is that the correct answer is **not**

What you need to remember about **addition** and **subtraction** with significant figures is that you only need to examine the **decimal portion** of the numbers, i.e. to the **right** of the *decimal point*.

In this case, you have

#32500 -># no decimal point, i.e.no decimals

#26823 -># no decimal point, i.e.no decimals

#56000 -># no decimal point, i.e.no decimals

This means that the answer **cannot** have a decimal point. In other words, the answer will be rounded to zero decimals. Consequently, you will have

#32500 + 26823 - 56000 = 3323#

That is the correct answer here, a value with *no decimals*. This value has a total of **four sig figs**, all given by its four non-zero digits.

If, for some reason, you want to **round this off** to two sig figs, then the answer would be

So remember, for **addition** and **subtraction**, you only have to look at the **decimal portion** of the numbers, not at the total number of sig figs they each have.