So what value do you want from the 4 cells in the row?
If you want to add them, use =SUM(A1

1) or just =A1+B1+C1+D1
If you want to multiply them, use =PRODUCT(A1

1) or =A1*B1*C1*D1
If you want the average, use =AVERAGE(A1

1)
If you want the minimum, use =MIN(A1

1)
If you want the maximum, use =MAX(A1

1)
and so on ...
The first lesson you need to learn as a beginner to Excel is that the
difficult thing is not finding the answer, but knowing what question it is
that you are trying to answer.