Incremental hlookup

Hello All

I was wondering if you could help me solve a quick problem I'm having. I have a spreadsheet as follows:

1 | 2 | 3 | 4 | 5 | 6
2.50 | 0.50 | 0.75 | 1.00 | 1.25 | 2.50

Say I entered "3" into a cell it would look up "0.75" but also add the cells before it so the total would be "2.50" + "0.50" + "0.75" = 3.75

Again, if I was to enter "5" into a cell it would look up "1.25" but also add the cells before etc to give me 6.00.

Is this possible at all?

Many thanks in advance...

here, try this:

=SUMIF(A1:E1,"<="&H1,A2:E2)

Or if your lookup numbers are not sequential, then:

=SUM(A2:INDEX(A2:F2,1,MATCH(A4,A1:F1,0)))

Cheers,

or even with values in b1 to z1
=SUM(B1:INDEX(B1:Z1,1,A1))
and put the number you want summed in a1