John received 20 gifts on his 12th birthday.  He received 8 fewer gifts on his 13th birthday.  How many total gifts did he receive between those two birthdays?
He got 20-8=12 gifts on his 13th birthday.
So he got 20+12=
<gadget id="calculator">20+12</gadget>
<output>32</output>
32 total gifts.

<result>32</result>