Math (6th grade)
posted by Sibel .
how many mm=1ft
how many cm=1yd
304.8 cm=how many ft
how many cm in 1 in?

check your answers here:
http://www.psinvention.com/zoetic/convert.htm 
The easy way to do this is to see that the units cancel and how to use conversion factors. I have memorized a fw conversions. For example,
2.54 cm = 1 inch
I know 12 inches = 1 ft.
I know 3 feet = 1 yard. Here how to do the ?mm = 1 ft.
We know 2.54 cm = 1 inch
We know 12 inches = 1 ft.
We know 10 mm = 1 cm.
Start with what we have. We have 1 ft.
We want to go to mm.
1 ft x (factor to inches) x (factor to cm) x (factor to mm) = ??
Now all we need to do is substitute for the factors. When we do this, we note how to place the factor; we always do it so the unit we don't want cancels and the unit we want to keep doesn't cancel). Here is how it works.
1 ft x (12 inches/1 ft)Note that the unit ft cancels and the first factor has converted ft to inches. We just keep the process going. Th final string looks like this.
1 ft x (12 in/1 ft) x (2.54 cm/1 inch) x (10 mm/cm) = ?? mm. 
to hard