A piece of paper has 8 grids counting from left to right and 5 grids counting from top to bottom. How many grids are there in total?
一张纸从左往右数有8个格子，从上往下数有5个格子，一共有多少个格子．
<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<result>40</result>