Question

1 metel sheet is 1.2 mm thick
how many sheets must be put together to have a thickness of 1.44 cm?

Answer 1

Change them to the same unit.

1.2mm and chang 1.44 cm to 14.4 mm  (1 cm = 10 mm)
Now divide
1.44/1.2  and you will get 12 sheets.