The answer is 36-3c.
We can find the answer this way:
The original cookies he has: 36
Let the number of cookies he gave to each friend be c.
As he gives to 3 friends, the number of cookies he gave away would be 3 multiply c, which makes 3c.
To find how much he has left,we can deduct the number of cookies he gives away(3c) from the original number of cookies(36).
We can then get the equation to find the number of cookies left: 36-3c.
Hope it helps!
