Tính hợp lý:
D=(-30)+(-29)+....+48+49+50
E=250:\([175-[50+3.5^2(2014+2015^{40})^0]]\)
F=\((6^{27}:6^{25}):[780:[5.89-\left(125+5.7^2\right)+5.11]]\)
E = 250:{175 - [50+ 3.52( 2014 + 2015"}°]}
F = ( 627:625):{780: [5.89 - ( 125 +5.72) + 5.11]}
làm ơn giúp
49.77-302+23.49
(612:610):{780:[5.89-(125+5.72)+5.11]}
217+[579+(-117)+(79)
nêu cách làm và kết quả nha
a) 8.39.125 b) 49.77 -30^2 + 23. 49 c) 2340 : [ 5.89-(125 +5.7^2 ) + 5.11]
a) Ta có: \(8\cdot39\cdot125\)
\(=\left(8\cdot125\right)\cdot39\)
\(=1000\cdot39=39000\)
b) Ta có: \(49\cdot77-30^2+23\cdot49\)
\(=49\cdot77+49\cdot23-30^2\)
\(=49\cdot\left(77+23\right)-900\)
\(=49\cdot100-9\cdot100\)
\(=100\cdot\left(49-9\right)\)
\(=100\cdot40=4000\)
c) Ta có: \(\frac{2340}{5\cdot89-\left(125+5\cdot7^2\right)+5\cdot11}\)
\(=\frac{2340}{5\left(89+11\right)-125-5\cdot7^2}\)
\(=\frac{2340}{5\cdot100-5\cdot25-5\cdot49}\)
\(=\frac{2340}{5\left(100-25-49\right)}=\frac{2340}{5\cdot26}=\frac{2340}{130}=18\)
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.
tính 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+50-999-888-777-666-555-444-333-222-111
nhanh nhé
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+4
7+48+49+50-999-888-777-666-555-444-333-222-111= -3720
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~
tìm n, biết:\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{n\left(n+2\right)}< \frac{2014}{2015}\)
Tính cách hợp lí
d) 54+( -37+10-54+67)
e) ( 326-43)+( 174-57)
f) ( 351-875) - ( 125-149)
g) -418 -{ -218-[ -118-(-131)] +2017}
h) -2 +7 + -12+17+....+ -52 + 57
i) - 30+ -29 + ...+ 48+49+50
d. 54-54+67-37+10
=40
e. 326+174-43-57
=400
f. 351+149-875-125
=-500