Here's a selection of number idioms divided into three categories. Each example is followed by a picture for better understanding of the idiom. I hope you find it helpful.
I 1, 2, 3, ...
- Two heads are better than one!
 |
www.aei.org |
 |
indianexpress.com |
- Two's company, three's a crowd!
 |
photo.net |
- First come, first served.
 |
www.granfondovienna.com |
- It was six of one and half a dozen of the other.
 |
photoaspire.wordpress.com |
- I just put two and two together.
 |
thinkjarcollective.com |
- You could kill two birds with one stone.
 |
sodahead.com |
 |
jobjoy.com |
- You have a one-track mind!
 |
genius.com |
- I was in two minds whether or not to go.
 |
hjenglish.com |
II Millions, thousands
- I wouldn't have thought she would have done such a bad thing - not in a million years!
- Thank you again and again - you're one in a million!
 |
flickr.com |
- I believe you! Thousands wouldn't!
 |
psychologytoday.com |
III Third time lucky
- The decision was made at the eleventh hour.
 |
mentalfloss.com |
- Have you tried this app? It's second to none.
- I've failed twice before, but I won't give up. You know what they say: third time lucky (US - third time is the charm).
 |
whats-thesayinganswers.com |
- All our work was in vain. We are back to square one.
 |
guernseydonkey.com |
- Ann, are you ready? No, I've lost my phone, my keys, my glasses, ... I'm all at sixes and sevens this week.
 |
sangeethibrahim.com |
- Sometimes I feel people are (two or) ten a penny in today's world.
 |
keepcalm-o-matic.co.uk |
- I was on cloud nine when I got married.
- You are not having second thoughts about going to college, are you?
- The news of his sickness knocked her for six.
Do you often use number idioms? Can you add some more?