The question asks to complete the factor pair of 30.

For the factor pair involving $2$:

• Divide $30$ by $2$: $30 \div 2 = 15$

So, the factor pair is $2 \times 15$. The missing number is 15.

Would you like further explanation or help with related problems?

Here are 5 related questions for deeper understanding:

1. What are all the factor pairs of 30?
2. How can you determine if a number is a factor of another number?
3. What are the prime factors of 30?
4. How does finding factor pairs relate to multiplication and division?
5. Can negative numbers also be part of factor pairs?

Tip: When finding factor pairs, start with 1 and work upward until you reach the square root of the number.