thank you @manalimodi48… But the thing i still don’t get is there are 10 columns as well isn’t it?

And for example when you finding the sum of tens, you’re only doing the last row (10th row) . What happened to the other tens in the other raws; and the same goes for the 9s.

No I’m finding sum of 10s in all the 10 columns. There is only one 10 and nine 9s in the last row. So the sum of 9s in last row will be 81(9 * 9) and sum of 10 will be 10 (10 * 1). For last second row, the sum of 9s will be 72(9 * 8) and sum of 10s will be 20(10 * 2). You gotta do this process till you reach the row number 1 in which there are no nines and ten 10s. Then, find sum of all the 10s which will be 100(1st row)+90(2nd row)+80…+10(10th row). Sum of 9s will be 0(1st row)+9(2nd row)+18(3rd row)…+81(10th row).