226-365-135+374
=(-365-135)+(226+374)
=-500+600
=100
18(10-12+12(18+10)
=18.334
=6012
72.30+31./-30/-3./30/
=???? ko hiu ban trinh bay hiu
1-2+3-4+...+199-200
=1 - 2 + 3 - 4 + ... + 199 - 200
= (1 -2 + 3 - 4) + (5 - 6 + 7 - 8) ..... + (197 - 198 + 199 - 200) có 50 cặp
= -2 . 50
= -100