Question

$$\begin{array}{ccc}4& 3& 8\\ 9& 5& \\ 2& 7& 6\end{array}$$

What is the missing number in the $3\times 3$ magic square?

Answer 1

The sum of numbers in any row or column or diagonal of the magic square is the same.

The sum of numbers in 1st row = 4 + 3 + 8 = 15.
It is same for all rows, columns and diagonals.

So in 2nd row, 9 + 5 is 14, the missing number is $15-14=1$.