The product of $4 \times 5$ is:

$4 \times 5 = 20$

Would you like any details on this, or do you have any questions?

Here are five related questions to explore:

1. What is $4 \times 6$?
2. If you have 4 groups of 7 objects, how many objects are there in total?
3. How can you use addition to solve $4 \times 5$?
4. What is the result of $5 \times 5$?
5. What is the area of a rectangle with a length of 4 and a width of 5?

Tip: Multiplication is a faster way to add the same number multiple times.