1. **Problem statement:** We need to find the number of ways to select 3 gifts from a list of 20 possible wedding presents. 2. **Formula used:** This is a combination problem because the order of selection does not matter. The formula for combinations is: $$ C(n, r) = \frac{n!}{r!(n-r)!} $$ where $n$ is the total number of items, $r$ is the number of items to choose, and $!$ denotes factorial. 3. **Apply the formula:** Here, $n=20$ and $r=3$. $$ C(20, 3) = \frac{20!}{3!(20-3)!} = \frac{20!}{3! \times 17!} $$ 4. **Simplify the factorial expression:** $$ \frac{20 \times 19 \times 18 \times 17!}{3! \times 17!} = \frac{20 \times 19 \times 18}{3 \times 2 \times 1} $$ 5. **Calculate the numerator and denominator:** Numerator: $20 \times 19 \times 18 = 6840$ Denominator: $3 \times 2 \times 1 = 6$ 6. **Divide to find the result:** $$ \frac{6840}{6} = 1140 $$ **Final answer:** There are 1140 ways to select 3 gifts from 20 possible wedding presents.