verb agreement with measurements and amounts
A quantity taken as one amount versus units taken one by one.
When a measurement or amount is one quantity, the verb is singular: Five miles is too far. When the units are separate items, the verb is plural: Five miles remain unmarked. Money, time, and weight follow the same split.
Examples
UseTen pounds is enough.
UseTen pounds were stacked on the bench.
AvoidTen pounds are enough (when you mean one weight).