If 20 counters are the whole set, what fraction of the set is 16 counters?

16 out of 20 is 16/20.

You can simplify that fraction by factoring the numerator and denominator and looking for common factors:
2*2*2*2 is the numerator 16
2*2*5 is the denominator 20
so we can divide both numerator and denominator by 2*2 or 4 to get the simplified fraction:
16/4 = 4
20/4 = 5
So our final simple fraction is 4/5

4/5

If 12 counters are 2/5, then what is the one?

To find the fraction of the set that 16 counters represent, you can use the concept of dividing the part (16) by the whole (20). Here's how you can calculate it:

1. Identify the whole set: The question states that the whole set consists of 20 counters.

2. Determine the part: The question asks for the fraction that represents 16 counters.

3. Write the fraction: To express 16 counters as a fraction of the whole set, you can write it as 16/20.

4. Simplify the fraction: To simplify the fraction, you can divide both the numerator and the denominator by their greatest common divisor. In this case, the greatest common divisor of 16 and 20 is 4 (since both numbers are divisible by 4). Dividing both the numerator and denominator by 4 gives you the simplified fraction 4/5.

Therefore, 16 counters represent 4/5 (or four-fifths) of the whole set.