A monitor is 21 inches by 12 inches.  There are 100 dots per inch.  How many total pixels are there?
The display is 21*100=
<gadget id="calculator">21*100</gadget>
<output>2_100</output>
2100 pixels across.
The display is 12*100=
<gadget id="calculator">12*100</gadget>
<output>1_200</output>
1200 pixels tall.
That means there is a total of 2100*1200=
<gadget id="calculator">2100*1200</gadget>
<output>2_520_000</output>
2,520,000 pixels.

<result>2_520_000</result>