John has to replace the ball bearings for machines he works with.  He has 10 machines and they take 30 ball bearings each.  It normally costs $1 per ball bearing but right now there is a sale where they are only $.75.  Also since he is buying in bulk he gets a further 20% discount.  How much money did he save by buying them all during the sale rather than 1 at a time?
He needs to replace 30*10=
<gadget id="calculator">30*10</gadget>
<output>300</output>
300 ball bearings.
The normal price is 300*1=$
<gadget id="calculator">300*1</gadget>
<output>300</output>
300.
Because of the sale he only has to pay 300*.75=$
<gadget id="calculator">300*.75</gadget>
<output>225</output>
225.
He then gets a discount which shaves another 225*.2=$
<gadget id="calculator">225*.2</gadget>
<output>45</output>
45 off the price.
That means he only pays 225-45=$
<gadget id="calculator">225-45</gadget>
<output>180</output>
180.
So he saved 300-180=$
<gadget id="calculator">300-180</gadget>
<output>120</output>
120.

<result>120</result>