L = 3/21 + 3/41 - 3/61 / 9/21 + 9/41 - 9/61 - 11/35 - 11/10 - 11/23 / 2/35 - 2/10 - 2/23
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70=?
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+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=?
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=1275
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50.
Có ai rảnh đâu mà đi ngồi cộng ngần đấy số ra.
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50
NHỚ KẾT BẠN VỚI MÌNH NHA '-'
1 + 2 + 3 +...+ 50
Dãy trên có số số hạng là:
\(\left(50-1\right)+1=50\) (số)
Tổng của chúng là:
\(\frac{\left(50+1\right)\cdot50}{2}=1275\)
Vậy tổng của chúng là 1275
~Học tốt~
Bài 1: Thực hiện phép tính:
1, 4/23 + 5/21 + 0,5 - 4/23 + 16/21
2, (1/3 + 12/67 + 13/41)-(79/67 - 28/41)
3, 12,5 x (-5/7)+1,5 x (-5/7)
4, 3/8x19 1/3- 3/8x33 1/3
5, 5/7x(-3/11)+5/7x(-8/11)+2 5/7
6, (-5/11:13/8-5/11:13/5)- giá trị tuyệt đối của -1/33
1: \(\dfrac{4}{23}+\dfrac{5}{21}+\dfrac{1}{2}-\dfrac{4}{23}+\dfrac{16}{21}\)
\(=1+\dfrac{1}{2}\)
\(=\dfrac{3}{2}\)
2: \(\left(\dfrac{1}{3}+\dfrac{12}{67}+\dfrac{13}{41}\right)-\left(\dfrac{79}{67}-\dfrac{28}{41}\right)\)
\(=\dfrac{1}{3}+\dfrac{12}{67}+\dfrac{13}{41}-\dfrac{79}{67}+\dfrac{28}{41}\)
\(=\dfrac{1}{3}\)
a) 21/47 + 9/45 +26/47 + 4/5
= (21/47 + 26/47) + (9/45 + 4/5)
=1+1 = 2
b) 15/12 + 5/13 - 3/12 - 18/13
= (15/12 - 3/12) + (18/13 - 5/13)
=1+1 = 2
c) 13/25 + 6/41 - 38/25 + 35/41 - 1/2
= (38/25 - 13/25) + (35/41 + 6/41) + 1/2
= 1+1 + 1/2 = 5/2
d) 27/23 + 5/21 - 4/23 + 6/21 + 1/2
= (27/23 - 4/23) + (6/21 - 5/21) + 1/2
= ..........................
Đúng không? Phần sau mình tính sao ra kết quả lạ lắm, tính giúp mình.
(-3/4+2/3):5/11+(-1/4+1/3):5/11
a)|x-13|-35-45=-47
b)(4+x).(x+3)=0
c)25-(5-x)=120-(28-5)
so sanh A va B
A=2/15 + 2/35 + 2/63 + 2/99 +2/143 va B=11/40
tính M/N
M=4/7*31 + 6/7*41 + 9/10*41 +7/10/57 N=7/19*31 + 5/19*43 + 3/23*43 + 11/23*57
thực hiện phép tính một cách hợp lí
38/11 + ( 16/13 + 6/11 )