G= (1313/1414+10/160)-(130/140-1515/1616)
thực hiện phép tính bằng cách hợp lý :
a/(-2013) . 2014 + 1007 .26
b/(1313/1414 + 10/160) - (130/140 - 1515/1616)
a.(-2013).2014+1007.26
=(-2013).2.1007+1007.26
=(-4026).1007+1007.26
=1007.(-4026+26)
=1007.(-4000)
=-4028000
b.(1313/1414 + 10/160) - (130/140 - 1515/1616)
=(13/14+1/16)-(13/140-(1/16+15/16)
=13/14+1/16-13/14+15/16
=(13/14+13/14)-(1/16+15/16)
=26/14-16/16
=26/14-1
=26/14-14/14
=12/14
=6/7
ấn đúng cho mình nhé
(\(\frac{1313}{1414}\)+\(\frac{10}{160}\))-(\(\frac{130}{140}\)-\(\frac{1515}{1616}\))
\(\left(\frac{1313}{1414}+\frac{10}{160}\right)-\left(\frac{130}{140}-\frac{1515}{1616}\right)\)
\(=\left(\frac{13}{14}+\frac{1}{16}\right)-\left(\frac{13}{14}-\frac{15}{16}\right)\)
\(=\frac{13}{14}+\frac{1}{16}-\frac{13}{14}+\frac{15}{16}\)
\(=\left(\frac{13}{14}-\frac{13}{14}\right)+\left(\frac{1}{16}+\frac{15}{16}\right)\)
\(=0+1\)
\(=1\)
Có (\(\frac{1313}{1414}\)+\(\frac{10}{160}\)) - (\(\frac{130}{140}\)-\(\frac{1515}{1616}\))
=\(\frac{13}{14}\)+\(\frac{1}{16}\)-\(\frac{13}{14}\)+\(\frac{15}{16}\)
=(\(\frac{13}{14}-\frac{13}{14}\)) + (\(\frac{1}{16}+\frac{15}{16}\))
=0+1=1
1111+1212+1313+1414+1515+1616 / 2020+2121+2222+2323+2424+2525 =?
\(\frac{2323+1313+1414+1515+1616}{4141+2222+2323+2424+2525}\)
=\(\frac{8181}{13635}\)
11+22+33+44+55+66+77+88+99+1010+1111+1212+1313+1414+1515+1616+.........+20162016=?
> , < , =
1313/1717.... 13/17
161616/202020.... 5/6
1414/1818.....7/8
1212/1616..... 1515/2424
1313/1717=13/17
=>1313/17 = 13/17
161616/202020 =16/20=4/5=24/30 ;5/6=25/30
=>161616/202020 <5/6
so sánh :
\(\frac{111111}{666665}\)và\(\frac{1212+1313+1414+1515+1616}{1717+1818+1919+2020+2121}\)
Ai làm đúng và nhanh nhất mk k cho
cái thứ hai lớn hơn
Ta có : \(\frac{1212+1313+1414+1515+1616}{1717+1818+1919+2020+2121}=\frac{12+13+14+15+16}{17+18+19+20+21}=\frac{28\cdot\frac{5}{2}}{38\cdot\frac{5}{2}}=\frac{14}{19}\)
Dễ thấy \(\frac{111111}{666665}< \frac{1}{2}\) ( do 111111 < 666665/2 ) và \(\frac{14}{19}>\frac{1}{2}\) ( do 14 > 19/2 )
Vậy \(\frac{111111}{666665}< \frac{1212+1313+1414+1515+1616}{1717+1818+1919+2020+2121}\)
Bài 5:
a,1111+1212+1313+1414+1515+1616/2020+2121+2222+2323+2424+2525
b,5.4:0,4x1420+4,5x780x3/3+6+9+12+.....+24+27
c,7,2:2x28,6+1,43x2x64/2+2+4+6+10+16+...110
1)tính 1 cách hợp lí: a) A=\(\left(\frac{1313}{1414}+\frac{10}{160}\right)-\left(\frac{130}{140}+\frac{1515}{1616}\right)\)
b)B=\(\left(\frac{2^6.3^5-9^2.4^3}{4^3.9^2-3^4.8^2}\right)\)
2)Chứng minh rằng:C=\(\frac{1}{101}+\frac{1}{102}+\frac{1}{103}+...+\frac{1}{200}>\frac{7}{12}\)
Mình làm luôn
a,A\(=\left(\frac{1313}{1414}-\frac{130}{140}\right)+\left(\frac{1515}{1616}+\frac{10}{160}\right)\)
\(=0+1\)
=1
b,Rút gọn p/s giống nhau ở tử và mẫu :26 với 82, 92 với 92, 35 với 34 thì còn3
Sau khi rút gọn rồi thì ta còn p/s:\(\frac{1.3-1.1}{1.1.1.1}=3\)
Câu 2 mình chịu
1313/1717 ..... 13/17 161616/202020 ....... 5/6
1414 ..... 7/8 1212/1616 ........1515/2424
1313/1717 = 13/17 161616/202020 < 5/6
1414 > 7/8 1212/1616 > 1515/2424
chúc bạn học tốt! ^_^
phần dưới cùng là cái underline đấy, ko phải dấu = đâu