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a) 50 : (5 × 2) = 50 :10 = 5
50 : (5 × 2) = 50 : 5 : 2 = 5
b) 28 : (2 × 7) = 28 : 14 = 2
28 : (2 × 7) = 28 : 2 : 7
= 14 : 7 = 2
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1. ( 76 x 28 ) : 7 = 2128 : 7 = 304
2. 76 x (28 : 7) = 76 x 4 = 304
1/ (76 x 28) : 7
= 2128 : 7
= 304
2/ (76 x 28) : 7
= 76 x ( 28 : 7)
= 76 x 4
= 304
Hok tốt
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a. ….= 61 692 : 4 = 15 423
….= 33 164 : 4 + 28 528 : 4
….= 8291 + 7132 = 15 423
b. ….= 387 079 : 7 = 55 297
….= 403 494 : 7 – 16 414 : 7
….= 57 642 - 2345 = 55 297
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Cách 1:
A. \(\dfrac{17}{19}\) x \(\dfrac{12}{15}\) x \(\dfrac{19}{17}\)
= (\(\dfrac{17}{19}\) x \(\dfrac{19}{17}\)) x \(\dfrac{12}{15}\)
= \(1\) x \(\dfrac{12}{15}\)
= \(\dfrac{4}{5}\)
Cách hai:
A; \(\dfrac{17}{19}\) x \(\dfrac{12}{15}\) x \(\dfrac{19}{17}\)
= \(\dfrac{68}{95}\) x \(\dfrac{19}{17}\)
= \(\dfrac{4}{5}\)
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câu A cách 1
\(\dfrac{17}{19}\times\dfrac{12}{15}\times\dfrac{19}{17}\)
=\(\dfrac{17\times12\times19}{19\times15\times17}\)
=\(\dfrac{12}{15}\)
câu A cách 2
\(\dfrac{17}{19}\times\dfrac{12}{15}\times\dfrac{19}{17}\)
=\(\dfrac{17}{19}\times\dfrac{19}{17}\times\dfrac{12}{15}\)
=1 x \(\dfrac{12}{15}\)
=\(\dfrac{12}{15}\)
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a) Cách 1 : (3/4 + 1/2) x 5/7
= 5/4 x 5/7
= 25/28
Cách 2 : (3/4 + 1/2) x 5/7
= 3/4 x 5/7 + 1/2 x 5/7
= 15/28 + 5/14
= 25/28
b) Cách 1 : 5/7 x 13/21 + 2/7 x 13/21
= 65/147 + 26/147
= 13/21
Cách 2 : 5/7 x 13/21 + 2/7 x 13/21
= (5/7 + 2/7) x 13/21
= 1 x 13/21
= 13/21
câu c tự làm
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(33 164 + 28 528) : 4 = 61 692 : 4 = 15 423
= 33 164 : 4 + 28 528 : 4
= 8291 + 7132 = 15 423
Cách 1
28 x ( 7 - 2 )
= 28 x 5
= 140
Cách 2
28 x ( 7 - 2 )
= 28 x 7 - 28 x 2
= 196 - 56
= 140