Combination/Examples/2 from 3

Example of Combinations

There are $3$ combinations of $2$ objects taken $3$ at a time:

$a \, b \quad a \, c \quad b \, c$

Sources

• 1971: George E. Andrews: Number Theory ... (previous) ... (next): $\text {3-1}$ Permutations and Combinations: Example $\text {3-5}$