Pre-Algebra Examples

$12$ , $23$ , $45$ , $45$ , $56$ , $65$ , $78$ , $87$ , $98$

Step 1

The mean of a set of numbers is the sum divided by the number of terms.

$\frac{12 + 23 + 45 + 45 + 56 + 65 + 78 + 87 + 98}{9}$

Step 2

Simplify the numerator.

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Step 2.1

Add $12$ and $23$ .

$\frac{35 + 45 + 45 + 56 + 65 + 78 + 87 + 98}{9}$

Step 2.2

Add $35$ and $45$ .

$\frac{80 + 45 + 56 + 65 + 78 + 87 + 98}{9}$

Step 2.3

Add $80$ and $45$ .

$\frac{125 + 56 + 65 + 78 + 87 + 98}{9}$

Step 2.4

Add $125$ and $56$ .

$\frac{181 + 65 + 78 + 87 + 98}{9}$

Step 2.5

Add $181$ and $65$ .

$\frac{246 + 78 + 87 + 98}{9}$

Step 2.6

Add $246$ and $78$ .

$\frac{324 + 87 + 98}{9}$

Step 2.7

Add $324$ and $87$ .

$\frac{411 + 98}{9}$

Step 2.8

Add $411$ and $98$ .

$\frac{509}{9}$

Step 3

Divide.

$56.\overline{5}$

Step 4

The mean should be rounded to one more decimal place than the original data. If the original data were mixed, round to one decimal place more than the least precise.

$56.6$