____centigram = 1.7 microgram

# of cg = 1.7ug x 1mg/1000ug x 1cg/10mg = 0.00017cg
but its wrong

___ milliseconds = 7 microseconds

# of ms = 7us x 1ms/1000us = 0.07us
but the answer key says its 0.007us

0.00017 cg looks ok to me. Perhaps you are supposed to enter 1.7 x 10^-4 cg. Also, sometimes the answer is counted wrong if you don't enter the unit.

For the second problem, 7 divided by 1000 = 0.007. Your set up is ok; you just didn't do the math correctly.

thank you DrBob

To convert between centigrams (cg) and micrograms (ug), or between milliseconds (ms) and microseconds (us), you need to use the appropriate conversion factors.

For the first example, if 1.7 micrograms is equal to a certain number of centigrams, you can use the following conversion factor chain:

1.7 ug x (1 mg / 1000 ug) x (1 g / 1000 mg) x (1 cg / 10 mg)

This will give you the value in centigrams. However, the calculation you provided is incorrect. The correct calculation should be:

1.7 ug x (1 cg / 10 ug) = 0.17 cg (not 0.00017 cg)

For the second example, to convert 7 microseconds to milliseconds, you can use the conversion factor:

7 us x (1 ms / 1000 us)

This will give you the value in milliseconds. Again, the calculation you provided is incorrect. The correct calculation should be:

7 us x (1 ms / 1000 us) = 0.007 ms (not 0.07 ms)

So, the correct conversions are:
- 1.7 micrograms = 0.17 centigrams
- 7 microseconds = 0.007 milliseconds