Question

what fraction is equivalent to 1/10 with the denominator as _____/1000

Answer 1

1/10 is equal to 100/1000, as that way, both the numerator and the denominator are multiplied by 100.
This works because the number multiplying the top and bottom are equal, therefore resulting in no net change.

Answer 2

1 X
------=-------
10 1000

Cross multiply
1x 1000 (=1000)
1000/10 (=100)
100