The total length was 6 m.
One of the tables was 1.8 m
Subtract 1.8 from 6 to find the total length of the other two tables:
6 - 1.8 = 4.2m
The other two tables are the same size, so now divide 4.2 m by 2:
4.2 / 2 = 2.1
The other tables are 2.1 m long.
