Matt needs to buy new plates for his home.  He only wants to do dishes once a week.  Three days a week it is only him and his son eating and they use 1 plate each.  On the remainder of the days, his parents join them and everyone uses 2 plates that day.  How many plates does he need to buy?
So for 3 of the days, there are 1+1=2 people eating.
So for those days they use 3*2=
<gadget id="calculator">3*2</gadget>
<output>6</output>
6 plates.
On 7-3=4 days the parents join them.
On those days there are 2+2=
<gadget id="calculator">2+2</gadget>
<output>4</output>
4 people eating.
They use 4*2=
<gadget id="calculator">4*2</gadget>
<output>8</output>
8 plates.
So they use 8*4=
<gadget id="calculator">8*4</gadget>
<output>32</output>
32 plates.
That means they use a total of 32+6=
<gadget id="calculator">32+6</gadget>
<output>38</output>
38 plates.

<result>38</result>