Meaning trap
add up
make sense
If something 'adds up', it means it makes sense or seems reasonable.
Don't mix these meanings
Same phrase, different job.
If something 'adds up', it means it makes sense or seems reasonable.
Another meaning of 'add up' is 'calculate the total'; compare the examples to keep the meanings separate.
Hear it in context
Notice where the phrase sounds natural.
Her explanation just didn’t add up.
When I looked at the evidence, it didn’t add up, so I started to doubt the results.
Fix the pattern
One small grammar move makes it sound right.
Not: Her story doesn't add up with the facts.
Say: Her story doesn't add up. / Her story doesn't fit the facts.
'Add up' works alone here — don't tack 'with' on it.
Which sounds natural?
Tap the one a native speaker would say.
'Doesn't add up' is the natural way to flag something illogical or suspicious; the formal version is stiff.
Build natural chunks
Words that usually travel with it.
(not) add up
- doesn't
- something
- it all
- just
Don't confuse it
Related
Other meanings and phrases to compare.
- add up (calculate the total) — Another meaning of 'add up' is 'calculate the total'; compare the examples to keep the meanings separate.