WHY is it so important to include units when expressing numbers?

An airplane flying parallel to the ground undergoes two consecutive displacements. the first is 76 km at 39.8◦ west of north, and the second is 156 km at 59.9◦ east of north. what is the magnitude of the plane’s total displacement? answer in units of km. 020 (part 2 of 2) 10.0

What do you think car designers do if the damage caused by a crash test is too severe?

What is the coefficient of kinetic friction μk between the block and the tabletop?