\(\frac{9\times15\times21\times12\times20}{5\times6\times45\times18\times4}=?\)
Những câu hỏi liên quan
Tính nhanh:\(\frac{1\times2\times3+2\times4\times6+3\times6\times9+4\times8\times12+5\times10\times15}{1\times3\times5+2\times6\times10+3\times9\times15+4\times12\times20+5\times15\times25}-\frac{1+2+3+2+4+6+3+6+9+4+8+12+5+10+15}{1+3+5+2+6+10+3+9+15+4+12+20+5+15+25}\)
\(\frac{4}{2\times4}+\frac{4}{4\times6}+\frac{4}{6\times8}+\frac{4}{8\times10}+...+\frac{4}{16\times18}+\frac{4}{18\times20}\)
Gọi tổng là A ta có:
\(A.2=\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+...+\frac{2}{18.20}\)
\(A.2=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{18}-\frac{1}{20}\)
\(A.2=\frac{1}{2}-\frac{1}{20}\)
\(A=\frac{9}{20}:2=\frac{9}{40}\)
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CHO A = \(\frac{2\times9\times8+3\times12\times10+4\times15\times12+...+98\times297\times200}{2\times3\times4+3\times4\times5+4\times5\times6+...+98\times99\times100}\)
TÍNH A\(^2\)
\(A=\frac{2\cdot9\cdot8+3\cdot12\cdot10+4\cdot15\cdot12+...+98\cdot297\cdot200}{2\cdot3\cdot4+3\cdot4\cdot5+4\cdot5\cdot6+...+98\cdot99\cdot100}\)
\(=\frac{2\cdot1\cdot3\cdot3\cdot4\cdot2+3\cdot1\cdot4\cdot3\cdot5\cdot2+...+98\cdot1+99\cdot3+100\cdot2}{2\cdot3\cdot4+3\cdot4\cdot5+...+98\cdot99\cdot100}\)
\(=\frac{1\cdot3\cdot2\cdot\left(2\cdot3\cdot4+3\cdot4\cdot5+...+98\cdot99\cdot100\right)}{2\cdot3\cdot4+3\cdot4\cdot5+...+98\cdot99\cdot100}\)
\(=1\cdot3\cdot2\)
\(=6\)
\(A^2=6^2=36\)
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So sánh các số :
A=\(\frac{1\times2+2\times4+3\times6+4\times8+5\times10}{3\times4+6\times8+9\times12+12\times16+15\times20}\)
và
B=\(\frac{111111}{666665}\)
giải chi tiết giùm nha
A) \(\frac{1}{6}\) = 0,1666666665
B) 0,1666669167
\(\frac{1}{6}\) < \(\frac{111111}{666665}\)
Bạn lấy tử chia cho mẫu là ra
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Tính nhanh giá trị biểu thức :
\(\frac{1\times3\times5+2\times6\times10+4\times10\times12+7\times21\times35}{1\times5\times7+2\times10\times14+4\times20\times28+7\times35\times49}\)
1 x 3 x 5 + 2 x 6 x 10 + 4 x 10 x 12 + 7 x 21 x 35 / 1 x 5 x 7 + 2 x 10 x 14 + 4 x 20 x 28 + 7 x 35 x 49
= 3 / 7 + 6 / 14 + 10 x 2 x 6 / 10 x 2 x 28 + 21 / 49
= 3 / 7 + 6 / 14 + 6 / 28 + 21 / 49
= 3 / 7 + 6 / 14 + 3 / 14 + 3 / 7
= ( 3 / 7 + 3 / 7 ) + ( 6 / 14 + 3 / 14 )
= 6 / 7 + 9 14
= 12 / 14 + 9 / 14
= 21 / 14
nho hem
lm dau tien lun do
dung 100% nha
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A. \(35\times34+35\times38+65\times75+65\times45=\) =
\(B.3\times25\times8+4\times37\times6+2\times18\times12\)=
A . 1190 + 1330 + 4875 + 2925
= 10320
B . 600 + 888 + 432
= 1920
TK MK NHA MK ĐG BỊ ÂM ĐIỂM
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SGK Kết nối tri thức với cuộc sống - Trang 69
24 tháng 8 2023 lúc 0:08
Tính.
a) \(\dfrac{5\times6\times12}{6\times12\times7}\) b) \(\dfrac{9\times8\times15}{15\times9\times16}\)
a) \(\dfrac{5\times6\times12}{6\times12\times7}=\dfrac{5}{7}\)
b) \(\dfrac{9\times8\times15}{15\times9\times16}=\dfrac{1}{2}\)
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\(\frac{4}{3\times6}+\frac{4}{6\times9}+\frac{4}{9\times12}+\frac{4}{12\times15}\)
\(\frac{4}{3.6}+\frac{4}{6.9}+\frac{4}{9.12}+\frac{4}{12.15}\)
\(=\frac{4}{3}.\left(\frac{3}{3.6}+\frac{3}{6.9}+\frac{3}{9.12}+\frac{3}{12.15}\right)\)
\(=\frac{4}{3}.\left(\frac{1}{3}-\frac{1}{6}+\frac{1}{6}-\frac{1}{9}+\frac{1}{9}-\frac{1}{12}+\frac{1}{12}-\frac{1}{15}\right)\)
\(=\frac{4}{3}.\left(\frac{1}{3}-\frac{1}{15}\right)\)
\(=\frac{4}{3}.\left(\frac{5}{15}-\frac{1}{15}\right)\)
\(=\frac{4}{3}.\frac{4}{15}=\frac{16}{45}\)
Dấu . là nhân nha
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\(\frac{4}{3.6}+\frac{4}{6.9}+\frac{4}{9.12}+\frac{4}{12.15}\)
\(=\frac{4}{3}.\left(\frac{3}{3.6}+\frac{3}{6.9}+\frac{3}{9.12}+\frac{3}{12.15}\right)\)
\(=\frac{4}{3}.\left(\frac{1}{3}-\frac{1}{6}+\frac{1}{6}-\frac{1}{9}+\frac{1}{9}-\frac{1}{12}+\frac{1}{12}-\frac{1}{15}\right)\)
\(=\frac{4}{3}.\left(\frac{1}{3}-\frac{1}{15}\right)\)
\(=\frac{4}{3}.\frac{4}{15}=\frac{16}{45}\)
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\(A=\frac{4}{3.6}+\frac{4}{6.9}+\frac{4}{9.12}+\frac{4}{12.15}\)
\(=>\frac{3}{4}A=\frac{3}{3.6}+\frac{3}{6.9}+\frac{3}{9.12}+\frac{3}{12.15}\)
\(=>\frac{3}{4}A=\left(\frac{1}{3}-\frac{1}{6}\right)+\left(\frac{1}{6}-\frac{1}{9}\right)+\left(\frac{1}{9}-\frac{1}{12}\right)+\left(\frac{1}{12}-\frac{1}{15}\right)\)
\(=>\frac{3}{4}A=\frac{1}{3}-\frac{1}{15}\)
\(=>\frac{3}{4}A=\frac{4}{15}\)
\(=>A=\frac{4}{15}:\frac{3}{4}\)
\(=>A=\frac{4}{45}\)
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Xem thêm câu trả lời
\(\frac{4}{3\times6}+\frac{4}{6\times9}+\frac{4}{9\times12}+\frac{4}{12\times15}\)
\(\frac{4}{3.6}+\frac{4}{6.9}+\frac{4}{9.12}+\frac{4}{12.15}\)
\(=\frac{4}{3}\left(\frac{3}{3.6}+\frac{3}{6.9}+\frac{3}{9.12}+\frac{3}{12.15}\right)\)
\(=\frac{4}{3}\left(\frac{1}{3}-\frac{1}{6}+\frac{1}{6}-\frac{1}{9}+\frac{1}{9}-\frac{1}{12}+\frac{1}{12}-\frac{1}{15}\right)\)
\(=\frac{4}{3}\left(\frac{1}{3}-\frac{1}{15}\right)\)
\(=\frac{4}{3}.\frac{4}{15}=\frac{16}{45}\)
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giải:
\(\frac{4}{3x6}\)+\(\frac{4}{6x9}\)+\(\frac{4}{9x12}\)+ \(\frac{4}{12x15}\)
= \(\frac{4}{3}\)x(\(\frac{3}{3x6}\)+ \(\frac{3}{6x9}\)+\(\frac{3}{9x12}\)+\(\frac{3}{12x15}\))
=\(\frac{4}{3}\)x(1-\(\frac{1}{15}\))
=\(\frac{4}{3}\)x\(\frac{14}{15}\)
=\(\frac{56}{45}\)
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