The ratio of the numbers A and B is 5:2, the number B is 70, what is the number A?
甲乙两数的比是5：2，乙数是70，甲数是多少．
<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">70 * (5/2)</gadget>
<output>175</output>

<result>175</result>