1 mũ 4 = 1
1*3*4*2 = 24*
24*- -98 = 2352
Đ/S : 2352
1 mũ 4 = 1
1*3*4*2 = 24*
24*- -98 = 2352
Đ/S : 2352
B= 1 + 2+3+4+...+2022 + 2023
C= 2 + 4 + 6+...+ 98 + 100
D= 1 + 3 + 5 +...+ 97 + 99
E= 10 + 14 + 18 +... + 98 + 102
tinh nhanh
a) 36*17-8.7*25+64*17-0.87*650
b) 2009*14+1994+2007*2008/2008+2008*505+504*2008
c) 1*1+2*2+3*3+4*4+5*5+...+98*98
cho S=2+2^2+2^3+2^4+2^5+...+2^98+2^99.Chứng tỏ S chia hết cho 14
Tính nhanh
a) 1 - 2 - 3 + 4 + 5 - 6 -7 + 8 + .... + 97 - 98 - 99 + 100
b) 1 - 6 + 11 - 16 + ... + 91 - 96
c) 2 - 5 + 8 - 11 + 14 - 17 +... + 98 - 101
c. G = 1 -2 -3 + 4 + 5 - 6 - 7 + ....... + 97 - 98 - 99 + 100
d. H = 2100 - 299 - 298 -..........- 2 - 1
e. I = 2 - 5 + 8 - 11 + 14 - 17 + ....+ 98 - 101
Tính hợp lí nhất
1, 2155– (174 + 2155) + (-68 + 174) 2, -25 . 72 + 25 . 21 – 49 . 25 3, 35(14 –23) – 23(14–35) 4, 8154– (674 + 8154) + (–98 + 674) 5, – 25 . 21 + 25 . 72 + 49 . 25 6, 27(13 – 16) – 16(13 – 27)
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7, –1911 – (1234 – 1911) 8, 156.72 + 28.156 9, 32.( -39) + 16.( –22) 10, –1945 – ( 567– 1945) 11, 184.33 + 67.184 12, 44.( –36) + 22.( –28)
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A=1+(2)+3+(-4)+...+(-100)+101
B=(-2)+4+(-6)+....+(-98)+100
C=4+(-14)+(-24)+34+44+...+1994+2004
1) 7. (3x+5)+2.(7x+14)=98. 2) 4. (x -5)+3.(x+7)=22
3) 5.(4-x) +7.(x-2)=24. 4) 3.(x -5)+6.(x+3)=12
5) 4-x+5.(x+2)=38. 6) 5.( x-3)+2.(x+8)=22
7) 5.(x-7)+10.(4+x)=20. 8) 4.(x+10)+8.(x-3)=24
9) 4.(5-x)+5.(x-2)=15. 10) 4.(x-1)+3.(x-2)=-1
a, 3-4+5-6+7-8+...+99-100
b, 2-5+8-11+14-17+...+98-101
c, 1+2+(-3)-4+5+6-...-99
1+2+3+.....+99=100
10+12+14+...+198+200
10+12+14+....+98+100
1+3+5+.......+47+49
1+3+5+.....+997+999
2+4+6+....+886 + 888