So for this it's asking to multiply 10,000 glass beads by the length of 0.4 cm.
So to make it easier let's just make it a fraction.
This will make it 4/10 (because 0.4 is just 4 tenths of a whole number)
So now we can upscale the sizes to the proper ratio. This ratio being the thousands.
4000/10000
Meaning the answer is 4000cm in length.