\(\dfrac{1996.1995-996}{1000+1996.1994}\)
1 tính nhanh
\(\frac{1996.1995-996}{1996.1994+1000}\)
xin lỗi các bạn
1996*1995-1996*1994=1996
(1996*1995-996)-(1996*1994)=1996-996=1000
(1996*1995-996)-(1996*1994+1000)=1996-996-1000=0
=>(1996*1995-996)/(1996*1994+1000)=1( vì tử số bằng mẫu số)
\(\frac{1996.1995-996}{1996.1994+1000}=\frac{\left(1000+996\right).1995-996}{\left(1000+996\right).1994+1000}\)
\(=\frac{1000.1995+996.1995-996}{996.1994+1000.1994+1000}=\frac{1000.1995+996\left(1995-1\right)}{996.1994+1000\left(1994+1\right)}\)
\(=\frac{1000.1995+996.1994}{996.1994+1000.1995}\)=1
\(\frac{1996\cdot1995-996}{1996\cdot1994+1000}\)
\(=\frac{1996\cdot\left(1994+1\right)-996}{1996\cdot1994+1000}\)
\(=\frac{1996\cdot1994+\left(1996-996\right)}{1996\cdot1994+1000}\)
\(=\frac{1996\cdot1994+1000}{1996\cdot1994+1000}\)
\(=1\)
Các bạn giúp mk hai câu này với nhé:
\(\frac{1995.1993-18}{1975.1993.1994}\)
\(\frac{1996.1995-996}{1000+1996.1994}\)
Giải ra giúp mk nhé!
\(\frac{1995.1993-18}{1975.1993.1994}\)\(=\frac{1995-18}{1975.1994}\)
\(=\frac{1977}{1975.1994}\)
\(=\frac{1975+2}{1975.1994}\)
\(=\frac{2}{1994}=\frac{1}{997}\)
\(\frac{1996.1995-996}{1000+1996.1994}\)\(=\frac{1995-996}{1994+1000}\)
\(=\frac{999}{1994+1000}\)
\(=\frac{999}{1994+999+1}\)
\(=\frac{1}{1994+1}=\frac{1}{1995}\)
Bài tập hè nà:
1,Tính giá trị biểu thức một cách hợp lý
a,\(\dfrac{1993+1993.1994}{1992.1995+1995}\)
b\(\dfrac{399.45+55.399}{1995.1996-1991.1995}\)
c,\(\dfrac{1996.1995-996}{1000+1996.1994}\)
d,\(\dfrac{1998.1996+1997.11+1985}{1997.1996-1995.1996}\)
A= \(\dfrac{1993\left(1994+1\right)}{1995\left(1992+1\right)}\)=1
B=\(\dfrac{399\left(45+55\right)}{1995\left(1996-1991\right)}\)=\(\dfrac{399.5.100}{399.5.5}\)=100
C=\(\dfrac{1996.1994+1996-996}{1000+1996.1994}\)=1
rut gon
a)\(\frac{125.81.7}{49.75.27}\)
b)\(\frac{48.25-48.11-48}{16.23-16.10}\)
c)\(\frac{15\left[4.17+17.5\right]}{18.25.34}\)
d)\(\frac{1996.1995-996}{1000+1996.1994}\)
\(a,\frac{125\cdot81\cdot7}{49\cdot75\cdot27}=\frac{25\cdot5\cdot9\cdot9\cdot7}{7\cdot7\cdot15\cdot5\cdot3\cdot9}=\frac{25\cdot9}{7\cdot15\cdot3}=\frac{5\cdot5\cdot3\cdot3}{7\cdot3\cdot5\cdot3}=\frac{5}{7}\)
\(b,\frac{48\cdot25-48\cdot11-48}{16\cdot23-16\cdot10}=\frac{1200-528-48}{368-160}=\frac{624}{208}=3\)
\(c,\frac{15\cdot\left[4\cdot17+17\cdot5\right]}{18\cdot25\cdot34}=\frac{15\cdot\left[17\cdot\left(4+5\right)\right]}{15300}=\frac{15\cdot153}{15300}\)
\(=\frac{2295}{15300}=\frac{3}{20}\)
\(d,\frac{1996\cdot1995-996}{1000+1996\cdot1994}=\frac{3982020-996}{1000+3980024}=\frac{3981024}{3981024}=1\)
1,tính nhanh
\(\frac{1996.995-996}{1996.1994+1000}\)
mình cần rất gấp
Sửa đề : \(\frac{1996\cdot1995-996}{1996\cdot1994+1000}\)
\(=\frac{1996+\left(1994+1\right)-996}{1996\cdot1994+1000}\)
\(=\frac{1996\cdot1994+\left(1996-996\right)}{1996\cdot1994+1000}\)
\(=\frac{1996\cdot1994+1000}{1996\cdot1994+1000}=1\)
15+(1000-998)+(998-996)+(996-994)+....+(102-100)+(100-98)=
bỏ ngoặc rút gọn rồi tính
15+(1000-998)+(998-996)+(996-994)+....+(102-100)+(100-98)
= 15+1000-998+998-996+996-994+....+102-100+100-98
= 15 + 1000 - 98 = 917
\(15+\left(1000-998\right)+\left(998-996\right)+\left(996-994\right)+...+\left(102-100\right)+\left(100-98\right)=15+2+2+...+2=15+226\times2=467\)
15+(1000-998)+(998-996)+...+(102-100)+(100-98)
=15+1000-998+998-996+...+102-100+100-98
=15+1000+(998-998)+(996-996)+...+(102-102)+(100-100)-98
=15+1000+0+0+...+0+0-98
=917
\(y=\frac{998}{1000}+\frac{997}{1000}+\frac{996}{1000}+.......+\frac{1}{1000}\)
y = \(\frac{998}{1000}+\frac{997}{1000}+\frac{996}{1000}+......+\frac{1}{1000}\)
<=>998+997+996+....+1(*)
Số các số hạng là:(998-1)+1=998
tổng của 2 số đầu dãy và cuối dãy là:998+1=999
(*)=999.998:2=997002;2=498501
=>y=\(\frac{498501}{1000}\)
1996 *1995 -996-1000 -1996* 1996
1996 * 1995 - (996 + 1000 + 1996*1996)
= 1996*1995 - (1996 x (1 + 1996))
= 1996*(1995 - 1996 - 1)
= 1996* -2
=-3992
1996 * 1995 - (996 + 1000 + 1996*1996)
= 1996*1995 - (1996 x (1 + 1996))
= 1996*(1995 - 1996 - 1)
= 1996* -2
=-3992
Tính: -996 + 998 - 1000 + 1002 - ........- 2012+ 2014