a) 24.(16-5)+16.(24-5)
=24.16-24.5+16.24-16.5
=32.24-40.5
=...................
31.(-81)+31.(-81)-31
=31[(-81)-81-1]
=31.(-163)
=...........................
13(23+22)-3(17+28)
=13.23+13.22-3.17-3.18
=...................................
a) \(24.\left(16-5\right)+16.\left(24-5\right)\)
\(=24.16-24.5+16.24-16.5\)
\(=24\left(16+16\right)+5\left(-24-16\right)\)
\(=24.32+5.\left(-40\right)\)
\(=768+\left(-200\right)\)
\(=568\)
b) \(31.\left(-18\right)+31.\left(-81\right)-31\)
\(=31.\left[\left(-18\right)+\left(-81\right)-1\right]\)
\(=31.\left(-100\right)\)
\(=-3100\)
c) \(13.\left(23+22\right)-3.\left(17+28\right)\)
\(=13.45-3.45\)
\(=45.\left(13-3\right)\)
\(=45.10\)
\(=450\)
