John used to buy 4 coffees a day for $2 each.  They raised the price by 50% so he cut the number of coffees he drinks in half.  How much money does he save per day compared to what he used to spend?
He now buys 4/2=
<gadget id="calculator">4/2</gadget>
<output>2</output>
2 coffees.
The new price is 2*.5=$
<gadget id="calculator">2*.5</gadget>
<output>1</output>
1 more than the old price.
So he now pays 2+1=$
<gadget id="calculator">2+1</gadget>
<output>3</output>
3 per coffee.
So he spends 3*2=$
<gadget id="calculator">3*2</gadget>
<output>6</output>
6.
He used to spend 4*2=$
<gadget id="calculator">4*2</gadget>
<output>8</output>
8.
So he saves 8-6=$
<gadget id="calculator">8-6</gadget>
<output>2</output>
2 per day.

<result>2</result>