12/35 : 2/6 = ( 12 * 6 ) / ( 35 * 2 ) = ( 12 * 3 ) / 35 = 36/35 = 1 ( 1/35 )
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15/17 : 5 = 15 / ( 17 * 5 ) = 3 / 17
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4 : 20/21 = ( 4 * 21 ) / 20 = 21 / 5 = 4 ( 1/5 ) = 4,2
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8 ( 3/4 ) : 2 ( 1/3 ) = 35/4 : 7/3 = ( 35 * 3 ) / ( 4 * 7 ) = ( 5 * 3 ) / 4 = 15/4 =
= 3 ( 3/4 ) = 3,75