Question

What is bigger, 4,000,000 mm or 4km

Answer 1

We need to have the same unit to compare.

We can change km to mm

1 km is 1,000,000 mm so,
4 km is 4,000,000 mm

4,000,000 mm = 4,000,000 mm
Both are equal

Answer 2

4,000,000 mm is equal to 4 km

4,000,000 mm = 4 km