Explicație pas cu pas:
1) 9×6-[100-(6×7+10)]+5×5=54-[100-(42+10)]+25=54-[100-52]+25
=54-48+25=6+25=31
2) [81:9+7×(2:2+6):7]:2=[9+7×(1+6):7]:2=[9+7×7:7]:2=[9+49:7]:2
=[9+7]:2=16:2=8
3) 24:4+4×[6:6 +(55-5):10]-0:77=6+4×[`1+50:10]-0:77=6+4×[1+5]-0
=6+4×6-0=6+24-0=30
4) [0:2+3:(20-17)+4-4:(100-98)]×1×10=[0+3:3+4-4:2]×10=[1+4-2]×10
=[5-2]×10=3×10=30