How to use SUMIF function in Excel | Practical Example | Solving a Real Problem

[@chromedata9996]

So how do i add certain values and sort the values under the different headings for example the plank size is 2.5 and few are 2.5 and few are 3.5 and they have to be multiplied by their corresponding value in another cell and after which the column 2.5 should only have values that correspond to 2.5 and the rest should be blank the next column 3.5 should have calculation for 3.5 only and the rest of the cells should be blank and so on