a) 274+(158+26) b) 29+132+237+868+163 c) 98.31+62 d) 10+11+12+13+...+99 f) (1+3+5+7+... + 217) (135135.137 - 135.137137 e) 3.25.8+4.37.6+2.38.12
Tính nhanh
29+132+237+868+736
3.25.8+4.37.6+2.38.12
Biết làm câu b
=24.25+24.37+24.38
=24.(25+24+38)
=24.87
=2088
cau a là
29 + 135 + 234 + 865 + 766
=(135 + 865) + ( 234 + 766) + 29
= 1000 + 1000 + 29
= 2000 + 29
= 2029
câu b
3.25.8 + 4.37.6 + 2.38.12
= 3.8.25 + 4.6.37 + 2.12.38
=24.25 + 24.37 + 24.38
=24.(25+27+38)
=24.87
=2088
a=2029
b=2088
k cho mình nha chúc bạn học tốt
A) 10+11+12+13+......+99 B) 1+6+11+16+......+46+51 C) (1+3+5+7+......+2017) (135135.137 - 135.137137)
a) \(10+11+12+...+99=\dfrac{\left(99+10\right)\left(\dfrac{99-10}{1}+1\right)}{2}=4905\)
b) \(1+6+11+...+51=\dfrac{\left(51+1\right)\left(\dfrac{51-1}{5}+1\right)}{2}=286\)
c) \(\left(1+3+5+...+2017\right)\left(135135.137-135.137137\right)=\left(1+3+5+...+2017\right)\left[1001\left(135,137-135.137\right)\right]=\left(1+3+5+...+2017\right).0=0\)
a)
=10+(11+99)+(12+98)+.....+(54+56)+55
=10+55+110+110+...+110
=10+55+110.(99-11):2
=10+55+110.44
=65+4840=4905
1. (-12)+(-15)+(-31) | 2. 25+37-59 | 3. (-12)+13-(-60)
4. 24:(-2)+(-5) | 5. 32.(-2)+64 | 6. 18.3+(-50):5
7. (-24)+37+163+(-176) | 8. 125+217+(-625)+529 | 9. 29+132+237+868+763
10. (-87)+126+187+74 | 11. 29.87+29.13 | 12. 123.(-29)-23.(-29)
13. 31.(-18)+31.(-81)-31 | 14.(-12).47+(-12).52+(-12) | 15. 24.(16-5)-16.(24-5)
16. 29.(29-3)-19.(29-13) | 17. -452-(-67+75-452) | 18. -(-171+89+223)-(71-111)+223
19. 21.83-3.7.(-17) | 20. 35-{12-[-14+(-2)]} | 21.5+10+15+20+....+1000
22. 3-6+9-12+....+195-198
Tính nhanh:
a) 246+58+54+242
b)11+12+13+....+17+18+19
c)64.16+81.84+17.16
d)3.25.8+4.37.6+2.38.12
tinh nhanh
a, 4.7.76+8.24
b,136.48+16.272+68.20.2
c,3.25.8+4.36.6+2.38.12
d,10+11+12+13+....+99
e,1+6+11+16+....+46+51
Tính nhanh:
a) 23.56 + 56.77;
b) 32.19 + 32;
c) 35.34 + 35,86 + 65.75 + 65.45;
d) 43.17 + 29.57 + 13.43 + 57;
e) 3.25.8+4.37.6 + 2.38.12
f) 64.16+81.84+17.16
a) 23.56 + 56.77 = (23 + 77).56 = 100.56 = 5600.
b) 32.19 + 32 = 32.(19 +1) = 32.20 = 640.
c) 35.34 + 35.86 + 65.75 + 65.45 = 35.(34 + 86) + 65.(75 + 45)
= 120.35+120.65 -120.(35 + 65) = 12000.
d) 43.17 + 29.57 +13.43 + 57 = 43.(17 +13) + 57.(29 +1)
= 43.30 + 57.30 = 30. (43+57) = 3000.
e) 3.25.8 + 4.37.6 + 2.3812 - 24.25 + 24.37 + 24.38
= 24.(25 + 37 + 38) = 2400.
f) 64.16 + 81.84+17.16 = 16.(64+17)+81.84 = 16.81+81.84
= 81.(16 + 84) = 8100
Tính nhanh:
a) 23.56 + 56.77;
b) 32.19 + 32;
c) 35.34 + 35,86 + 65.75 + 65.45;
d) 43.17 + 29.57 + 13.43 + 57;
e) 3.25.8+4.37.6 + 2.38.12
f) 64.16+81.84+17.16
a) 23.56 + 56.77 = (23 + 77).56 = 100.56 = 5600.
b) 32.19 + 32 = 32.(19 +1) = 32.20 = 640.
c) 35.34 + 35.86 + 65.75 + 65.45 = 35.(34 + 86) + 65.(75 + 45)
= 120.35+120.65 -120.(35 + 65) = 12000.
d) 43.17 + 29.57 +13.43 + 57 = 43.(17 +13) + 57.(29 +1)
= 43.30 + 57.30 = 30. (43+57) = 3000.
e) 3.25.8 + 4.37.6 + 2.3812 - 24.25 + 24.37 + 24.38
= 24.(25 + 37 + 38) = 2400.
f) 64.16 + 81.84+17.16 = 16.(64+17)+81.84 = 16.81+81.84
= 81.(16 + 84) = 8100
mn giup minh nha
tinh nhanh
a, 35.34+35.86+65.75+65.45
b, 10+11+12+13+........+ 99
c,(1+3+5+7+....+2017).(135135.137 + 135.137137)
cam cac ban da giup minh
a)1200
b)4905
c) Mình nghĩ là bằng 0 nếu ở thừa số thứ 2 dấu''+'' là dấu''-''
Còn nếu là dấu''+'' thì mình chịu
a) 185 + 434+ 515 + 266 + 155
b) 652 + 327 + 148 + 15 + 73
c) 5 . 125 . 2 . 1 . 8
d) 8.12.125.2
e) 3.25.8.+4.37.6+2.38.12
a) 185+434+515+266+155 = (185+515)+(434+266)+155
= 700+700+155 = 1555
b. (652+148)+(327+73)+15=800+400+15=1215
c. (125*8)*(5*2)*1=1000*10*1=10000
d. (125*8)*(12*2)=1000*24=24000
e.3*25*4*2+4*37*6+2*38*12=600+888+912=2400
mik ik mik til lại cko nha! mấy bạn
a) 185 + 434+ 515 + 266 + 155
=(185+515)+(434+266)+155
=700+700+155
=1400+155
=1555
b) 652 + 327 + 148 + 15 + 73
=(652+147)+(327+73)+15
=800+400+15
=1215
c) 5 . 125 . 2 . 1 . 8
=10.1000
=10000
d) 8.12.125.2
=24.1000
=24000
e) 3.25.8.+4.37.6+2.38.12
=24.(25+37+38)
=24.100
=2400