Doxa sliced an apple into 8 pieces. She ate 1 slice, her sister ate 1 more than her, and her brother ate 1 more than her sister. How many slices of apple did they all eat?
Her sister ate 1 + 1 = 
<gadget id="calculator">1+1</gadget>
<output>2</output>
2 slices.
Her brother ate 2 + 1 = 
<gadget id="calculator">2+1</gadget>
<output>3</output>
3 slices.
They ate a total of 1 + 2 + 3 = 
<gadget id="calculator">1+2+3</gadget>
<output>6</output>
6 slices.

<result>6</result>