The number B is 2 less than the number A, and the number A is 5 times the number B. What is the product of the numbers A and B?
乙数比甲数少2，甲数是乙数的5倍．甲、乙两数的积是多少．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 5</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(1/2) * (5/2)</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>