SUM of Total Positive Changes in a Column

[MRADICE]

I have a list of various scrap materials inventory by weight (kg) that is reported out weekly. Here's an example:

MATERIAL CODE	MATERIAL TYPE	2-Jan-17	9-Jan-17	16-Jan-17	23-Jan-17	30-Jan-17	Feb-06-17	Feb-13-17	Feb-21-17	Feb-27-17
55213	ABS	1826	1826	2795	2896	2,896	0	2,104	2,512	3,526
59381	ABS	8949	8949	8111	3984	6,294	6,619	7,472	6,668	5,807

I want to see the total weight of scrap, by material, that was added to inventory. Is there a way to use SUMIF/SUMIFS function to show total positive changes or something else? Is there a way to do it without adding a second column to capture the cumulative changes?

Any help would be greatly appreciated!

[p45cal]

Difficult without a helper column.
If values are in cells C2:K2, total positive changes can be summed with (cell M2 copied down):
=SUMPRODUCT((D2:K2-C2:J2)*((D2:K2-C2:J2)>0))
You say totals by material, but you have materialcode and material type, so here's both:
Mat Code (cell N2 copied down):
=SUMIF($A$2:$A$3,$A2,$M$2:$M$3)
and Mat type: (cell O2 copied down):
=SUMIF($B$2:$B$3,$B2,$M$2:$M$3)

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