72420 - (11725 - 9428)= 7807 - ( 3655 + 977)=
72420-(11725-9428)=72420-2297=70123 7809-(3655+977)=7809-2808=5001
1) 2) \ 1) 2) -11725 -72420 \ +3655 -7807 9428 2297 \ 977 4632 ---------- ----------- \ --------- --------- 2297 70123 \ 4632 3175