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Bài giải
Ta có: \(\frac{49+\left(-49\right).\left(-2\right)}{7.21}\)
= \(\frac{49.1+49.2}{7.21}\)
= \(\frac{49.\left(1+2\right)}{7.21}\)
= \(\frac{49.3}{7.21}\)
= \(\frac{7.7.3}{7.7.3}\)
= \(1\)
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a: 12/21=4/7=8/14
4/56=1/14
b: 12/15=4/5=24/30
6/36=1/6=5/30
15/50=3/10=9/30
c: 63/77=9/11=81/99
60/108=5/9=55/99
-18/27=-2/3=-66/99
d: -26/-156=1/6=7/42
49/-14=-7/2=-147/42
32/112=2/7=12/42
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a) 9.6 − 9.3 18 = 9. 6 − 3 18 = 9.3 2.9 = 3 2
b) 49 + 7.49 49 = 49. 1 + 7 49 = 8
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Bài 1: \(49+7\cdot\frac{49}{49}=49+7\cdot1\)
\(=49+7=56\)
Bài 2: \(\frac{1}{3}:0,25+\frac{7}{6}\cdot\frac{4}{7}-60=\frac{1}{3}:\frac{1}{4}+\frac{7\cdot4}{6\cdot7}-60\)
\(=\frac{1}{3}\cdot\frac{4}{1}+\frac{4}{6}-60=\frac{4}{3}+\frac{2}{3}-60\)
\(=\frac{6}{3}-60=2-60=-58\)
cảm ơn bạn Phạm Trà Giang nhiều nha, nhưng bài 2 mik thấy đổi 0,25 thành phân số là bằng 1/4 mà bạn thử kiểm tra lại kết quả nhé!!! Mik ẫn cảm ơn bạn nhiều nha.
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\(\frac{7\cdot25-49}{7\cdot24+21}=\frac{7\cdot25-7\cdot7}{7\cdot24+7\cdot3}\)
\(=\frac{7\cdot\left(25-7\right)}{7\left(24+3\right)}\)
\(=\frac{7\cdot18}{7\cdot27}=\frac{2}{3}\)
\(@Cothanhkhe\)
\(\frac{3\times21}{14\times15}=\frac{1\times21}{14\times5}=\frac{21}{70}=\frac{3}{10}\)
\(\frac{49+7\times49}{49}=\frac{392}{49}=8\)