27-[3×(18-5×3)-3×2] - {4×[3×(2-1)]}=
27-[3×(18-5×3)-3×2] - {4×[3×(2-1)]}=
27-[3×(18-5×3)-3×2] - {4×[3×(2-1)]}=
$27-[3×(18-15)-6]-{4×[3×1)]=$
$27-[3×3-6]-{4×3}=$
$27-[9-6]-12=$
$27-3-12=12$
Spero che le future espressioni le riesca autonomamente e senza problemi!
$27-[3×(18-5×3)-3×2] - \{4×[3×(2-1)]\}$ =
= $27-[3×(18-15)-6] - \{4×[3×1]\}$ =
= $27-[3×3-6] - \{4×3\}$ =
= $27-[9-6]-12$ =
= $27-3-12$ =
= $12$