( 77-9×4-s)-5×5+10:2=5×2-0:4×7
(77-36-s)-25+5=10-0×7
( 41-s )-25+5=10-0
(41-s)-25+5=10
41-s-25=10-5
41-s-25=5
41-s=5+25
41-s=30
s=41-30
s=10
