(a) & (d) are correct.


for (b),
0.9 x 1000 = 900 m


for (c),
0.64 x 1000 = 640 g


...

for b) and c) you need to shift the decimal places 3 times to the right also since it's x 1000

When you shift until a point you don't see a digit in front of the decimal, and you've not shifted enough times yet,

write a 0 in and continue to shift . Repeat this until you've reached the required number of shifts.


For example, your 0.9

Shift right once gives you 9. There's no digit in front of the decimal point now, so add a zero to get 9.0

Now shift right again to get 90.

Then there's no digit in front of the 0 again. So add one zero again to get 90.0

Shift right again to get 900


You have now shifted a total of 3 times, which is what was required. So you can stop here and thus 217.9km = 217km 900m