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Bài 1:
a) 19/27+9/7+6/27+5/7+2/7
= (19/27+6/27) + (9/7+5/7+2/7)
=1 + 16/7
=23/7
b) 2/7 + 27/48 + 7/16 +45/63
= (2/7 + 45/63) + (27/48 +7/16)
= (2/7 + 5/7) + ( 9/16 + 7/16)
= 1 + 1
=2
c) Tính bằng cách bình thường
Bài 2:
6/11 + x = 1
x = 1-6/11
x = 5/11
Bài làm
a) \(\frac{19}{27}+\frac{9}{7}+\frac{6}{27}+\frac{5}{7}+\frac{2}{7}\)
\(=\frac{27}{27}+\frac{16}{7}\)
\(=1+\frac{16}{7}\)
\(=\frac{7}{7}+\frac{16}{7}\)
\(=\frac{23}{7}\)
b) \(\frac{2}{7}+\frac{27}{48}+\frac{7}{16}+\frac{45}{63}\)
\(=\left(\frac{18}{63}+\frac{45}{63}\right)+\left(\frac{27}{48}+\frac{21}{48}\right)\)
\(=\frac{63}{63}+\frac{48}{48}\)
\(=1+1\)
\(=2\)
c) \(\frac{17}{23}+\left(\frac{4}{7}-\frac{6}{13}\right)\)
\(=\frac{17}{23}+\left(\frac{52}{91}-\frac{42}{91}\right)\)
\(=\frac{17}{23}+\frac{10}{91}\)
\(=\frac{1547}{2093}+\frac{230}{2093}\)
\(=\frac{1770}{2093}\)
Bài 2
\(\frac{6}{11}+x=1\)
\(x=1-\frac{6}{11}\)
\(x=\frac{11}{11}-\frac{6}{11}=\frac{5}{11}\)
Vậy \(x=\frac{5}{11}\)
8/27+4/5+19/27+11/15=(8/27+19/27) + (4/5+11/15)
= 1+ (12/15+11/15)
= 1+ 1/8/15=2/8/15
12/13+2/7+8/13+6/13+5/7=(12/13+8/13+6/13) + (2/7+5/7)
= 2+ 1
=3
Ý a có thể bạn chép nhầm 4/5 rồi
a) \(\frac{19}{27}+\frac{9}{7}+\frac{6}{27}+\frac{5}{7}+\frac{2}{27}\)
\(=\left(\frac{19}{27}+\frac{6}{27}+\frac{2}{27}\right)+\left(\frac{9}{7}+\frac{5}{7}\right)\)
\(=1+2=3\)
b) \(\frac{2}{7}+\frac{27}{48}+\frac{7}{16}+\frac{45}{63}\)
\(=\frac{2}{7}+\frac{9}{16}+\frac{7}{16}+\frac{5}{7}\)
\(=\left(\frac{2}{7}+\frac{5}{7}\right)+\left(\frac{9}{16}+\frac{7}{16}\right)\)
\(=1+1=2\)
7-17+27-37+...-1997+2007( có 201 số)
=(7-17)+(27-37)+...+(1987-1997)+2007( có 100 nhóm và 1 số)
=-10+(-10)+...+(-10)+2007( có 100 số -10 và 1 số)
=-10x100+2007
=-1000+2007=1007
Nay rảnh lại qua làm mấy bài lớp 4 ^^
Tui làm luôn kh ghi đề nhá
1,
\(\frac{2}{3}+\frac{8}{15}=\frac{6}{5}\)
\(\frac{2}{5}+\frac{2}{3}=\frac{16}{15}\)
\(\frac{2}{3}+\frac{5}{6}=\frac{3}{2}\)
2,
\(\cdot\frac{3}{7}+\frac{6}{5}+\frac{4}{7}\)
\(=\frac{3}{7}+\frac{4}{7}+\frac{6}{5}\)
\(=1+\frac{6}{5}\)
\(=\frac{11}{5}\)
\(\cdot\frac{6}{4}+\frac{7}{3}+\frac{4}{4}+\frac{3}{3}\)
\(=\frac{6}{4}+\frac{4}{4}+\frac{7}{3}+\frac{3}{3}\)
\(=\frac{10}{4}+\frac{10}{3}\)
\(=\frac{35}{6}\)
23+815=6523+815=65
25+23=161525+23=1615
23+56=3223+56=32
2,
⋅37+65+47⋅37+65+47
=37+47+65=37+47+65
=1+65=1+65
=115=115
⋅64+73+44+33⋅64+73+44+33
=64+44+73+33=64+44+73+33
=104+103=104+103
=356
5/7 < 4/3
7/2 > 4/79
2/5 < 6/10
15/23 < 1
1/4 = 3/12
27/9 > 2
27/36 > 2/9
14/15 < 1
7/6 > 7/9
51/17 = 3/1
tk mình nha bạn, mình kp vs bạn r đó. .. ^^
5/7 < 4/3 7/2 > 4/79 2/5 < 6/10 15/23 < 1 1/4 = 3/12 27/9 > 2 27/36 > 2/9 14/15 < 1 7/6 > 7/9 51/17 = 3/1
43 x 166 + 14 x 83
= 43 x ( 83 x 2 ) + 14 x 83
= (43 x 2) x 83 + 14 x 83
= 86 x 83 + 14 x 83
= ( 86 + 14 ) x 83
= 100 x 83
= 8300
43 x 166 + 14 x 83
= 43 x ( 83 x 2 ) + 14 x 83
= ( 43 x 2 ) x 83 + 14 x 83
= 86 x 83 + 14 x 83
= 83 x ( 86 + 14 )
= 83 x 100
= 8300
\(\frac{7}{2}\)- \(\frac{3}{2}\): x = \(\frac{5}{4}\)
\(\frac{3}{2}\): x = \(\frac{7}{2}-\frac{5}{4}\)
\(\frac{3}{2}\): x = \(\frac{14}{4}-\frac{5}{4}\)
\(\frac{3}{2}\): x = \(\frac{9}{4}\)
x = \(\frac{3}{2}:\frac{9}{4}\)
x = \(\frac{3}{2}x\frac{9}{4}\)
x = \(\frac{27}{8}\)
7/4 x 15/7 + 13/7 x 9/4 - 7/4 x2/7
=7/4 x 15/7- 7/4 x2/7+ 13/7 x 9/4
=7/4 x (15/7 - 2/7) + 13/7 x 9/4
=7/4 x 13 /7 + 13/7 x 9/4
=13/7 x (7/4+9/4)
=13/7 x 16/4
=13/7 x 4
=52/7
k mk nha
sorry câu trả lời vừa nãy mk ấn nhầm
7/4 x 15/7 + 13/7 x 9/4 - 7/4 x2/7
=7/4 x 15/7 - 7/4 x 2/7 + 13/7 x 9/4
sai rồi bạn ơi
phải là :
(83+27)X7-7x6-7x4
=110x7-7x6-7x4
=7x(110-6-4)
=7x100
=700
bài của bạn sai từ bước thứ 1 vì bạn viết thiếu 1 số 7