A cake of 400 grams is divided into eight equal parts. Nathalie eats one-eighth of the cake, and Pierre eats double what Nathalie ate. How much did Pierre eat, in grams?
Nathalie ate 1/8 * 400g = 
<gadget id="calculator">1/8*400</gadget>
<output>50</output>
50g of cake.
Pierre eats 2 * 50g = 
<gadget id="calculator">2*50</gadget>
<output>100</output>
100g of cake.

<result>100</result>