Find the Mean 71 , 75 , 74 , 80 , 83 , 86 , 90 , 85 , 81 , 80

$71$ , $75$ , $74$ , $80$ , $83$ , $86$ , $90$ , $85$ , $81$ , $80$

Step 1

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

$\frac{71 + 75 + 74 + 80 + 83 + 86 + 90 + 85 + 81 + 80}{10}$

Step 2

Simplify the numerator.

Add $71$ and $75$ .

$\frac{146 + 74 + 80 + 83 + 86 + 90 + 85 + 81 + 80}{10}$

Add $146$ and $74$ .

$\frac{220 + 80 + 83 + 86 + 90 + 85 + 81 + 80}{10}$

Add $220$ and $80$ .

$\frac{300 + 83 + 86 + 90 + 85 + 81 + 80}{10}$

Add $300$ and $83$ .

$\frac{383 + 86 + 90 + 85 + 81 + 80}{10}$

Add $383$ and $86$ .

$\frac{469 + 90 + 85 + 81 + 80}{10}$

Add $469$ and $90$ .

$\frac{559 + 85 + 81 + 80}{10}$

Add $559$ and $85$ .

$\frac{644 + 81 + 80}{10}$

Add $644$ and $81$ .

$\frac{725 + 80}{10}$

Add $725$ and $80$ .

$\frac{805}{10}$

Step 3

Cancel the common factor of $805$ and $10$ .

Factor $5$ out of $805$ .

$\frac{5 (161)}{10}$

Cancel the common factors.

Factor $5$ out of $10$ .

$\frac{5 \cdot 161}{5 \cdot 2}$

Cancel the common factor.

$\frac{5 \cdot 161}{5 \cdot 2}$

Rewrite the expression.

$\frac{161}{2}$

Step 4

Divide.

$80.5$