Pre-Algebra Examples

$30$ , $45$ , $56$ , $68$ , $16$ , $51$ , $25$ , $52$ , $18$ , $15$ , $30$ , $20$ , $33$ , $41$ , $43$ , $12$ , $19$ , $35$ , $28$ , $45$

Step 1

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

$\frac{30 + 45 + 56 + 68 + 16 + 51 + 25 + 52 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2

Simplify the numerator.

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Step 2.1

Add $30$ and $45$ .

$\frac{75 + 56 + 68 + 16 + 51 + 25 + 52 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.2

Add $75$ and $56$ .

$\frac{131 + 68 + 16 + 51 + 25 + 52 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.3

Add $131$ and $68$ .

$\frac{199 + 16 + 51 + 25 + 52 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.4

Add $199$ and $16$ .

$\frac{215 + 51 + 25 + 52 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.5

Add $215$ and $51$ .

$\frac{266 + 25 + 52 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.6

Add $266$ and $25$ .

$\frac{291 + 52 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.7

Add $291$ and $52$ .

$\frac{343 + 18 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.8

Add $343$ and $18$ .

$\frac{361 + 15 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.9

Add $361$ and $15$ .

$\frac{376 + 30 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.10

Add $376$ and $30$ .

$\frac{406 + 20 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.11

Add $406$ and $20$ .

$\frac{426 + 33 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.12

Add $426$ and $33$ .

$\frac{459 + 41 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.13

Add $459$ and $41$ .

$\frac{500 + 43 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.14

Add $500$ and $43$ .

$\frac{543 + 12 + 19 + 35 + 28 + 45}{20}$

Step 2.15

Add $543$ and $12$ .

$\frac{555 + 19 + 35 + 28 + 45}{20}$

Step 2.16

Add $555$ and $19$ .

$\frac{574 + 35 + 28 + 45}{20}$

Step 2.17

Add $574$ and $35$ .

$\frac{609 + 28 + 45}{20}$

Step 2.18

Add $609$ and $28$ .

$\frac{637 + 45}{20}$

Step 2.19

Add $637$ and $45$ .

$\frac{682}{20}$

Step 3

Cancel the common factor of $682$ and $20$ .

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Step 3.1

Factor $2$ out of $682$ .

$\frac{2 (341)}{20}$

Step 3.2

Cancel the common factors.

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Step 3.2.1

Factor $2$ out of $20$ .

$\frac{2 \cdot 341}{2 \cdot 10}$

Step 3.2.2

Cancel the common factor.

$\frac{2 \cdot 341}{2 \cdot 10}$

Step 3.2.3

Rewrite the expression.

$\frac{341}{10}$

Step 4

Divide.

$34.1$