a) 14 / 21 = ( 14 : 7 ) / ( 21 : 7 ) = 2 / 3
10 / 15 = ( 10 : 5 ) / ( 15 : 5 ) = 2 / 3
14 / 21 = 10 / 15 → fractii echivalente
14 × 15 = 21 × 10 → produsul mezilor = produsul extremilor
210 = 210
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b)
34 / 68 ≠ 24 / 72
34 × 72 ≠ 68 × 24
2 488 > 1 632
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c)
25 / 35 = 5 / 7 si 50 / 60 = 5 / 6 ⇒ 5 / 7 < 5 / 6
25 × 60 ≠ 35 × 50
1500 < 1750
25 / 35 ≠ 50 / 60
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d)
( 2 · 7 ) / ( 3 · 5 ) = 14 / 15 si ( 4 · 21 ) / ( 9 · 10 ) = 84 / 90
14 × 90 = 15 × 84
1 260 = 1 260
14 / 15 = 84 / 90 → fractii echivalente
