a: \(\left(-16\right)\cdot\left(-9\right)\cdot5=16\cdot9\cdot5=80\cdot9=720\)
b: \(-25\cdot144\cdot\left(-4\right)=25\cdot4\cdot144=144\cdot100=14400\)
c: \(\left(-125\right)\cdot2020\cdot\left(-8\right)\)
\(=2020\cdot125\cdot8=2020\cdot1000=2020000\)
d: \(\left(-15\right)\cdot999\)
\(=\left(-15\right)\left(1000-1\right)=-15\cdot1000+15\)
=-15000+15
=-14985
e: \(-48\cdot98=-48\left(100-2\right)\)
\(=-48\cdot100+48\cdot2\)
=-4800+96
=-4704
f: \(\left(-52\right)\cdot\left(-102\right)=52\cdot102\)
\(=52\left(100+2\right)=52\cdot100+52\cdot2\)
=5200+104
=5304
g: \(\left(-2021\right)\cdot\left(-15\right)+\left(-15\right)\cdot2020\)
\(=-15\left(-2021+2020\right)\)
\(=-15\cdot\left(-1\right)=15\)
h: \(87\cdot\left(-129\right)+129\cdot\left(-13\right)\)
\(=129\left(-87-13\right)\)
\(=129\cdot\left(-100\right)=-12900\)
k: \(\left(-1476\right)\cdot\left(-312\right)+1476\cdot\left(-12\right)\)
\(=1476\cdot312-1476\cdot12\)
\(=1476\left(312-12\right)=1476\cdot300=442800\)
l: \(121\cdot\left(-63\right)+63\cdot\left(-53\right)-63\cdot26\)
\(=63\left(-121-53-26\right)=63\cdot\left(-200\right)=-12600\)
m: \(\left(-134\right)+51\cdot134+\left(-134\right)\cdot48\)
=-134(1+51+48)
=-134*100
=-13400
n: \(124+\left(-52\right)\cdot124+\left(-124\right)\cdot\left(-47\right)\)
\(=124\left(1-52+47\right)=124\cdot\left(-4\right)=-496\)
o: \(-55\cdot78+13\cdot\left(-78\right)-78\cdot\left(-65\right)\)
\(=55\cdot\left(-78\right)+\left(-78\right)\cdot13+\left(-78\right)\cdot\left(-65\right)\)
\(=\left(-78\right)\left(55+13-65\right)=-78\cdot3=-234\)
p: \(45\cdot\left(-24\right)+\left(-10\right)\cdot\left(-12\right)\)
=-1080-120
=-1200
