So I have 2 separate columns (Column A / B for this matter) which use different formulas to increment for approximately different amounts. I need a formula / equation which when column B reaches a certain value in a row (say the value is reached in row 5 and the value I want is 4) it displays the value currently in row 5 of column A. So in the Example below Im looking for when column B reaches 4 (Which is in row 5) so it will display 10 because that is the the value in row 5 of column A.

`Column B Column A`

0 2
1 4
2 6
3 8
4 10

I have tried using an INDEX Match equation as follows

`INDEX(A1:A6;MATCH(4;B1:B6;0)).`

However with this I am getting a #N/A error. What should I be using to correct this?