Algebra-2

The missing number is 4.

 

Here's the reasoning: In Pascal's Triangle, as you mentioned, each number (except for the 1s on the edges of each row) is the sum of the two numbers directly above it in the previous row.

 

For the fifth row where the missing number (marked as “?”) is located, we look at the fourth row which has the numbers 1, 3, 3, 1.

 

The number in the fifth row that we need to find (the one replacing “?”) has the two numbers 3 and 1 directly above it from the fourth row. When we add these two numbers together (3 + 1), we get 4.

 

So the completed Pascal's Triangle would be: