Matthias has 40 soccer balls and 15 basketballs. 30 soccer balls and 7 basketballs have a hole in them. How many balls in total does Matthias have without holes in them?
Matthias has 40-30 = 
<gadget id="calculator">40-30</gadget>
<output>10</output>
10 soccer balls without holes.
Matthias has 15-7 = 
<gadget id="calculator">15-7</gadget>
<output>8</output>
8 basketballs without holes.
A total of 10+8 = 
<gadget id="calculator">10+8</gadget>
<output>18</output>
18 balls do not have holes.

<result>18</result>