If 15 counters are the whole set what is 3/5 of the set?

You need to multiply 15/1 X 3X5. 

Multiply the numerators (15 and 3) to get 45. 
Multiply the denominators (1 and 5) to get 5. 

So now you have reduced the fraction to 45/5 

Simplify it. 5 goes into 45 9 times. 

9 is your answer.

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