Zauważmy, że:

$2\cdot 3=6$  

$2\cdot 30=60$  

$2\cdot 300=600$  

zatem:

$a\text{)}62\cdot 10=620$  

$b\text{)}3270\cdot 10=32700$  

$c\text{)}52\cdot 100=5200$  

$d\text{)}19\cdot 1000=19000$  

$e\text{)}60\cdot 300=18000$  

$f\text{)}4000\cdot 90=360000$  

$g\text{)}800\cdot 11000=8800000$  

$h\text{)}120\cdot 5000=600000$