1+3+5+7+9+11+13+15+17+19=...
a: =35/17-18/17-9/5+4/5
=1-1=0
b: =-7/19(3/17+8/11-1)
=7/19*18/187=126/3553
c: =26/15-11/15-17/3-6/13
=1-6/13-17/3
=7/13-17/3=-200/39
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
4.24.52-(33.18+33.12)
=4.24.25-[27.(18+12)]
=(4.25).24-[27.30]
=100.24-810
=2400-810
=1590
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 = 1590
#HT#
1+3+5+7+9+11+13+15+17+19=
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 = 100
k mình nha
1+3+5+7+9+11+13+15+17+19
1+3+5+7+9+11+13+15+17+19
=(1+19)+(3+17)+(5+15)+(7+13)+(9+11)
=20+20+20+20+20
=20x5
=100
19+1 + 17+3 + 15+5 + 13+7 + 11+9=20 nhan 5 =100. nhé
1+3+5+7+...+19= ( 1 +19) + (2+18) = (3+17) +....+ (9+11)
=20+20+20+20+20
=100
x=1+3+5+7+9+11+13+15+17+19
\(x=1+3+5+7+9+11+13+15+17+19\)\(x=\left(1+19\right)+\left(3+17\right)+\left(5+15\right)+\left(7+13\right)+\left(9+11\right)\)
\(x=20+20+20+20+20\)
\(x=20\times5=100\)
1+3+5+7+9+11+13+15+17+19+20=?
1+3+5+7+9+11+13+15+17+19+20=
(1+19)+(3+17)+(5+15)+(7+13)+20=
20 +20 +20 + 20 +20=100
1+3+5+7+9+11+13+15+17+19+20
=(1+19)+(3+17)+(5+15)+(7+13)+(9+11)+20
=20+20+20+20+20+20
=20*6
=120
B=1+3-5-7+9+11-13-15+17+19-21-23
Bài 6 : Tính .
a , A = - 1 + 3 - 5 + 7 - 9 + 11 - 13 + 15 - 17
b , B = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - 11 -12 + 13 + 14 - 15 -16 + 17 + 18 - 19 - 20
a; A = -1 + 3 - 5 + 7 - 9 + 11 - 13 + 15 - 17
A = (-1 + 11) + ( 3 - 13) + (-5 + 15) + (7 - 17) - 9
A = 10 - 10 + 10 - 10 - 9
A = (10 - 10) + (10 - 10) - 9
A = 0 + 0 - 9
A = -9
b; B = 1+2-3-4+5+6-7-8+9+10-11-12+13+14-15-16+17+18-19-20
B = (1+2-3-4) + (5+6-7-8)+(9+10-11-12)+(13+14-15-16)+(17+18-19-20)
B= -4+(-4)+(-4)+(-4)+(-4)
B= -4 . 5
B= -20
1+3-5-7+9+11-13-15+17+19-...-397-399