Answer:
P-538=-1124
start subtracting with the left. 100's 30 then 8
100-1124=1024
1024-100=924
924-100=824
824-100=724
724-100=624
624-10=614
614-10=604
604-10=594
594-1=593
593-1=592
592-1=591
591-1=590
590-1=589
589-1=588
588-1=587
587-1=586
P=586
-586-538=-1124