You have not given us much to work with.
Suppose A1:F1 holds these values
100 110 120 130 140 150
And H1 hold the number 120 - the number you want to find
The the formula =MATCH(H1,A1:F1,0) will return 3 since the sought-after
number is in the third cell in the array A1:F1
Is this close to what you are trying to do?
best wishes
