Xiaojun is just 15 years old this year, and his height has reached 1.7 meters, which is 0.2 meters taller than his mother. How many meters is his mother's height?
小军今年刚15岁，身高就达到了1.7米，比妈妈还高0.2米，妈妈的身高是多少米？
<gadget id="calculator">1.7 - 0.2</gadget>
<output>1.5</output>

<result>1.5</result>