13/18 + 5/12 = 41/36
18 = 2 × 3^2
12 = 2^2 × 3
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c.m.m.m.c = 2^2 × 3^2 = 36 (numitorul comun celor doua fractii
prima fractie o amplificam cu 2
a doua feactie o amplificam cu 3
13/18 + 5/12 =
= 2×13/36 + 3×5/36 =
= 26/36 + 15/36 =
= 41/36
