Heaven and her younger brother want to buy school supplies, so they ask their father for money, who gives them $100 in total to use. Heaven buys two sharpeners and four notebooks at $5 each, and her brother uses the remaining amount to buy ten erasers at $4 each and some highlighters. How much money did Heaven's brother spend on highlighters?
Heaven spent 2*5=$
<gadget id="calculator">2*5</gadget>
<output>10</output>
10 on sharpeners.
She also spent 4*5 = $
<gadget id="calculator">4*5</gadget>
<output>20</output>
20 on notebooks.
Heaven's brother used 10*4 = $
<gadget id="calculator">10*4</gadget>
<output>40</output>
40 to buy erasers.
The total amount of money Heaven and her sister spent on sharpeners, notebooks, and erasers is 40+20+10 = $
<gadget id="calculator">40+20+10</gadget>
<output>70</output>
70.
The total amount of money her brother spent on highlighters is 100-70 =$
<gadget id="calculator">100-70</gadget>
<output>30</output>
30.

<result>30</result>