Grace's age is 3/8th the age of her grandmother. Her grandmother is twice the age of Grace's mother. If Grace's mother is 80 years old, how old is Grace?
Grace's grandmother is 2 * 80 years = 
<gadget id="calculator">2*80</gadget>
<output>160</output>
160 years old.
Grace's age is 3/8 * 160 years = 
<gadget id="calculator">3/8*160</gadget>
<output>60</output>
60 years old.

<result>60</result>