a) \(24\left(16-5\right)-16\left(24-5\right)\)
\(=24.16-24.5-16.24+16.5\)
\(=\left(24.16-16.24\right)-24.5+16.5\)
\(=5\left(-24+16\right)\)
\(=5\left(-8\right)\)
\(=-40\)
b) \(29\left(9-13\right)-19\left(29-13\right)\)
\(=29.9-29.13-19.29+19.13\)
\(=\left(29.9-19.29\right)-\left(29.13-19.13\right)\)
\(=29\left(9-19\right)-13\left(29-19\right)\)
= \(29.\left(-10\right)-13.10\)
\(=-290-130\)
\(=-420\)
c) \(31.\left(-18\right)+31.\left(-81\right)-31\)
\(=31\left[-18+\left(-81\right)\right]-31\)
\(=31.\left(-99\right)-31\)
\(=31\left(-99-1\right)\)
\(=31.\left(-100\right)\)
\(=-3100\)
d) \(-12.47+\left(-12\right).52+\left(-12\right)\)
\(=-12\left(47+52+1\right)\)
\(=-12.100\)
\(=-1200\)
e) \(\left(-6-2\right)\left(-6+2\right)\)
= \(-8.\left(-4\right)\)
\(=32\)
\(f\)) \(\left(-5+9\right)\left(-4\right)\)
\(=4.\left(-4\right)\)
\(=-16\)
