napkin math
The act of performing quick mathematics often as a means of estimation, as if done on…The act of performing quick mathematics often as a means of estimation, as if done on the back of a napkin (or in one's head).
Meaning
1 senses(Canada, US, uncountable)The act of performing quick mathematics often as a means of estimation, as if done on the back of a napkin (or in one's head).
Word family
1 related wordsRelatedback-of-the-envelope
Lessons for this word
1 lessons- A1Countable and uncountable nouns — Because it can be uncountable