Lookups combined with filter

[CelineT]

Hi all,
I have the following list:

Nbr date amount
1 1/1/15 20
1 1/1/16 25
1 1/10/16 30
2 1/1/08 19
2 1/1/09 20
3...

So basically several rows per nbr with different dates. Each date has a different amount (list of employees ans their salaries from tjat day onwards)

Per nbr I need to determine 2 amounts:
- on last known date (1: 30, for nbr 2: 20)
- on date 1/09/16: for nbr 1 it should give me the value of the last known date before that date so: 25. For nbr 2: 20

This must be possible i guess but i don't know how. Maybe with arrays?

I hooe someone can answer here

Thanks in advance