Answer:
126
Explanation:
The number of ways 4 items can be chosen from 9 is ...
9C4 = 9!/(4!(9-4)!) = 9·8·7·6/(4·3·2·1) = 9·7·2 = 126
There are 126 ways the 4 friends can make a pizza from 9 toppings.
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If you really mean to have a pizza with 44 toppings from a list of 99, there are about 2.765×10^28 ways to do that.
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