The new law will come into effect on the first day of next year.
The law is still in effect.
Word: "effect"
the same meaning

We can use this mathematical formula to solve the problem.
He doesn't know how to use a computer.
Word: "use"
the same meaning

Let's follow our great helmsman!
He followed his lecture with a question and answer period.
Word: "follow"
different meanings

The sum of all our troubles did not equal the misery they suffered.
The sum of forty pounds.
Word: "sum"
different meanings