Find the Mean 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12

$1$ , $2$ , $3$ , $4$ , $5$ , $6$ , $7$ , $8$ , $9$ , $10$ , $11$ , $12$

Step 1

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

$\frac{1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12}{12}$

Step 2

Simplify the numerator.

Add $1$ and $2$ .

$\frac{3 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12}{12}$

Add $3$ and $3$ .

$\frac{6 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12}{12}$

Add $6$ and $4$ .

$\frac{10 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12}{12}$

Add $10$ and $5$ .

$\frac{15 + 6 + 7 + 8 + 9 + 10 + 11 + 12}{12}$

Add $15$ and $6$ .

$\frac{21 + 7 + 8 + 9 + 10 + 11 + 12}{12}$

Add $21$ and $7$ .

$\frac{28 + 8 + 9 + 10 + 11 + 12}{12}$

Add $28$ and $8$ .

$\frac{36 + 9 + 10 + 11 + 12}{12}$

Add $36$ and $9$ .

$\frac{45 + 10 + 11 + 12}{12}$

Add $45$ and $10$ .

$\frac{55 + 11 + 12}{12}$

Add $55$ and $11$ .

$\frac{66 + 12}{12}$

Add $66$ and $12$ .

$\frac{78}{12}$

Step 3

Cancel the common factor of $78$ and $12$ .

Factor $6$ out of $78$ .

$\frac{6 (13)}{12}$

Cancel the common factors.

Factor $6$ out of $12$ .

$\frac{6 \cdot 13}{6 \cdot 2}$

Cancel the common factor.

$\frac{6 \cdot 13}{6 \cdot 2}$

Rewrite the expression.

$\frac{13}{2}$

Step 4

Divide.

$6.5$