Check below, please.
1) Let's effectuate those multiplications noticing the dot

Note that since we have3 zeros on the denominator we'll have 3 decimal places, similarly:
1 b.

Notice that we can write those decimal numbers as fractions.
2 a.

2 b.

3 a.

3 b.

4 a.

4 b.

5 a.

5 b.
