Chứng minh C=\(\frac{3}{5}+\frac{11}{13}+\frac{23}{25}+...+\frac{19799}{19801}\) >98
1) 15 - 98 + 91 - 75 + 98 - 91 - 13
2) 5 - ( 4 - 7 + 12 ) + ( 4 - 7 + 12 ) - 10
3) 20 - ( 25 - 98 + 12 ) + ( 25 - 98 - 72 )
4) - ( 17 - 4 + 13 + | -17 | + 13 )
5) | -16 | - ( 5 - 8 + 7) - ( - 5 ) - 8
6) -20 + ( 3 - 16 + 7 ) - ( 3 - 16 + 7 )
7) 32 - ( 5 - 8 + 32 ) + ( 5 - 8 + 6 )
8) -20 - ( 25 - 11 + 8 ) + ( 25 - 8 + 20 )
MÌNH VAN CÁC BN GIÚP MÌNH,MÌNH CHO 10TK
Bài 1: Thực hiện phép tính (Tính hợp lý nếu có thể) a) 7/30+(-12)/37+23/30+(-25)/37 b) 5/7⋅5/11+5/7⋅2/11-5/7⋅14/11 c) (-5)/7⋅3/13-5/7⋅10/13+1 5/7
Bài 1: 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)
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)
bài 1
a. 5/18 + 8/19 - 7/21 + ( -10/36 + 11/19 + 1/3) - 5/8
b.1/13 + ( -5/18 - 1/13 + 12/17 ) - ( 12/17 - 5/18 + 7/5 )
c.15/14 - (17/23 - 80/87 + 5/4)+(17/23 - 15/14 + 1/4 )
d.1/25 - 4/27 + ( -23/27 + -1/25 - 5/43 ) + 5/43 - 4/7
bài 2
a. x +1/3 = 3/4
b. x - 2/5 = 5/7
c. -x - 2/3 = -6/7
d. 4/7 - x = 1/3
e. x+ 5/2 = -3/2
f. x + 5/6 = -1/12
GIÚP MÌNH VỚI Ạ MÌNH CẢM ƠN TRƯỚC
TÍNH NHANH HOP LI
A) 5+(-7)+9+(-11)+13+(-15)+17+(-19)+21+(-23)
B) (-11)+13+(-15)+17+(-19)+21+(-23)+25+(-27)+29+(-31)+33
Câu hỏi: chung minh rang 2 day so nay la hop so a,1+2^7+3^11+5^13+7^17+11^19 b,21^123+23^124+25^125
4.24.5^2-(3^3.18+3^3.12)
31.15.7^2.4-31.49.40
1+2+3+4+5+6+7+8+9+10
1+3+5+7+9+11+13+15+19
2+6+10+14+22+23+26+34
5+8+11+14+17+20+23+26+29
1+6+11+16+21+26+31+36+41+47+51
10+13+16+19+22+25+28+31+34+37+40
5+7+9+11+13+15+17+3+8+13+18+23+28
4+7+10+13+16+19+5+9+13+17+21+25
Câu hỏi: chung minh rang 2 day so nay la hop so a,1+2^7+3^11+5^13+7^17+11^19
b,21^123+23^124+25^125