# Question #6af5d

##### 1 Answer

The answer must have three sig figs.

#### Explanation:

You need to take into account two rules for finding the number of significant figures an operation produces.

First, you have *multiplication*, for which you know that the answer **cannot** have more sig figs than the *least number* of sig figs you have for the numbers that are being multiplied.

In the first case, you have

#12.95 -> # four sig figs

#0.109 -> # three sig figs

The answer should only have **three** sig figs.

For the second multiplication, you have

#3.177 -># four sig figs;

#0.025 -># two sig figs

This time, the answer should only have **two** sig figs.

This means that you get

#12.95 * 0.109 - 3.177 * 0.025 = 1.41155 - 0.079425#

Round these off to the correct number of sig figs to get

#1.41 - 0.079#

Now you need to use the rules for finding the number of sig figs when you're subtracting two decimal numbers.

To find that, arrange the two numbers like this

#1.41#

#0.079#

Now, the last significant gidit in the result will correspond to the **leftmost** last significant digit of each number. The last significant digits of those numbers are

#1.4color(red)(1)#

#0.07color(red)(9)#

The one's that's furthest to the **left** is *hundreths mark*.

#1.41 - 0.079 = 1.331#

Rounded to the hundreths mark will result in

#1.41 - 0.079 = color(green)(1.33)#