Tính nhanh a,75+37-55-17 b,100-90+80-70+60-50 c,11+22+33+44 d,10-15+20-25+30-35+40 e,83+85+87+91+93+95+97+99+101 g,(100-90-10)*125

a, $75+37-55-17$

$=(75-55)+(37-17)$

$=20+20$

$=40$

b, $100-90+80-70+60-50$

$=10+10+10$

$=30$

c, $11+22+33+44$

$=11+11×2+11×3+11×4$

$=11×(1+2+3+4)$

$=11×10$

$=110$

d, $10-15+20-25+30-35+40$

$=(10+20+30+40)-(15+25+35)$

$=100-75$

$=25$

e, $83+85+87+91+93+95+97+99+101$

$=(83+87)+(85+95)+(97+93)+(91+99)+101$

$=170+180+190+190+101$

$=350+380+101$

$=831$

g, $(100-90-10)×125$

$=0×125$

$=0$

a,75+37-55-17

= (75-55) + ( 37-17)

= 20 + 20

= 40

b,100-90+80-70+60-50

= (100-90) + (80-70) + (60-50)

= 10 + 10 + 10

= 30

c,11+22+33+44

= (11+44) + (22+33)

= 55 + 55

= 110

e,83+85+87+91+93+95+97+99+101

= (83+101) + (85+99) + (87+97) + (91+93) + 95

= 184 + 184 + 184 + 184 + 95

=831

g,(100-90-10)*125

= 0 . 125

= 0

Mình lâu lắm mới làm những dạng như thế này nếu sai thì bạn mong bạn thông cảm ^^"