Sidney has 4 kittens and 3 adult cats.  She has 7 cans of cat food.  Each adult cat eats 1 can of food per day.  Each kitten eats 3/4 of a can per day.  How many additional cans of food does Sidney need to buy to feed all of her animals for 7 days.
Sidney has 3 adult cats * 1 can of food = 
<gadget id="calculator">3*1</gadget>
<output>3</output>
3 cans of food per day.
Sidney's adult cats will need 3 cans * 7 days = 
<gadget id="calculator">3*7</gadget>
<output>21</output>
21 cans for the week.
Sidney has 4 kittens * 3/4 cup of food = 
<gadget id="calculator">4*3/4</gadget>
<output>3</output>
3 cans of food per day.
Sidney's kittens will need 3 cans * 7 days = 
<gadget id="calculator">3*7</gadget>
<output>21</output>
21 cans for the week.
Sidney will need to buy 21 cans + 21 cans - 7 cans = 
<gadget id="calculator">21+21-7</gadget>
<output>35</output>
35 cans.

<result>35</result>