I have to generate a function on excel that does the following

the problem is about polynomial interpolation.

I have for example a column of values:

-100

0

100

200

300

400

First , I need to find the value in the table that is 2 point above

*the input value.*

For example , if my

*input value*is 118 the first value is 0.

Second, my real problem is how to select the next four values ( and use them else where).

For the same example, if we enter 118, the corresponding colum must be:

0

100

200

300

I dont know how to go from a cell to another cell using a formula.

I hope that you can understand me.

thank you for your help