Răspuns:
a) 8000×1000=8000000
5000×1000=5000000
20000×1000=20000000
70000×1000=70000000
400000×1000=400000000
900000×1000=900000000
b) 8000×100×2
=800000×2
=1600000
5000×100×2
=500000×2
=1000000
20000×100×2
=2000000×2
=4000000
700000×100×2
=70000000×2
=14000000
400000×100×2
=400000000×2
=80000000
900000×100×2
=900000000×2
=180000000