1.
see add 2
2.
If facts or events do not ~, they make you confused about a situation because they do not seem to be consistent. If something that someone has said or done adds up, it is reasonable and sensible.
Police said they arrested Olivia because her statements did not ~...
PHRASAL VERB: usu with neg, V P
3.
If small amounts of something ~, they gradually increase.
Even small savings can ~...
PHRASAL VERB: V P