\( 50-30 = 20 \). \( 20 < 40 \)
\( 90-80 = 10 \). \( 10 = 10 \)
\( 100-30 = 70 \). \( 70 > 50+20 \)
\( (30+50)-40 = 80-40 = 40 \). \( 40 > 30+60 \)
\( 60 \). \( 60 < 80-40 \)
\( 20+(70-30) = 20+40 = 60 \). \( 60 = 50+10 \)
Ответ: <, =, <, >, <, =.