Pre-Algebra Examples

$521 \cdot 45$

Step 1

Multiply $5$ by $1$ . Place the result in the next column in the result line. There is one result line for each digit in $45$ .


	$5$	$2$	$1$
$⨯$		$4$	$5$
			$5$

Step 2

Multiply $5$ by $2$ . Place the ones digit $(0)$ in the result line and carry the tens digit $(1)$ . There is one result line for each digit in $45$ .

	$1$
	$5$	$2$	$1$
$⨯$		$4$	$5$
		$0$	$5$

Step 3

Multiply $5$ by $5$ and add the carried $1$ . Place the ones digit $(6)$ in the result line and carry the tens digit $(2)$ . There is one result line for each digit in the $45$ .


	$5$	$2$	$1$
$⨯$		$4$	$5$
$2$	$6$	$0$	$5$

Step 4

Multiply $4$ by $1$ . Place the result in the next column in the result line. There is one result line for each digit in $45$ .


	$5$	$2$	$1$
$⨯$		$4$	$5$
$2$	$6$	$0$	$5$
		$4$

Step 5

Multiply $4$ by $2$ . Place the result in the next column in the result line. There is one result line for each digit in $45$ .


	$5$	$2$	$1$
$⨯$		$4$	$5$
$2$	$6$	$0$	$5$
	$8$	$4$

Step 6

Multiply $4$ by $5$ . Place the ones digit $(0)$ in the result line and carry the tens digit $(2)$ . There is one result line for each digit in $45$ .


		$5$	$2$	$1$
	$⨯$		$4$	$5$
	$2$	$6$	$0$	$5$
$2$	$0$	$8$	$4$

Step 7

Add the numbers in each column. In this case, add $5 + 0$ , then place the $5$ in the result line.


		$5$	$2$	$1$
	$⨯$		$4$	$5$
	$2$	$6$	$0$	$5$
$2$	$0$	$8$	$4$
				$5$

Step 8

Add the numbers in each column. In this case, add $0 + 4$ , then place the $4$ in the result line.


		$5$	$2$	$1$
	$⨯$		$4$	$5$
	$2$	$6$	$0$	$5$
$2$	$0$	$8$	$4$
			$4$	$5$

Step 9

Add the numbers in each column. In this case, add $6 + 8$ , then place the $4$ in the result line and carry the $1$ .


		$5$	$2$	$1$
	$⨯$		$4$	$5$
	$2$	$6$	$0$	$5$
$2$	$0$	$8$	$4$
		$4$	$4$	$5$

Step 10

Add the numbers in each column. In this case, add $2 + 0 + 1$ , then place the $3$ in the result line.


		$5$	$2$	$1$
	$⨯$		$4$	$5$
	$2$	$6$	$0$	$5$
$2$	$0$	$8$	$4$
	$3$	$4$	$4$	$5$

Step 11

Add the numbers in each column. In this case, add $0 + 2$ , then place the $2$ in the result line.


		$5$	$2$	$1$
	$⨯$		$4$	$5$
	$2$	$6$	$0$	$5$
$2$	$0$	$8$	$4$
$2$	$3$	$4$	$4$	$5$

Step 12

The result of $521 \cdot 45$ is $23445$ .

$23445$