*To put two and two together: to figure out something that seems obvious or logical.
He has been avoiding me lately and he never answers my calls. I´ve put two and two together and decided I´d better forget about him if he doesn´t care about me.
*Two heads are better than one: two people can think of an answer more quickly than only one.
My friend and I were having trouble doing the math exercise, but we managed to solve it in the end. I wouldn´t have been able to solve it on my own. I always say two heads are better than one.
*(There´s) No two ways about it: there´s only one solution to a problem, no other choice:
You have to go to the doctor whether you like it or not. There's no two ways about it.
*To be of two minds (over something): to be undecided, to vacillate between two alternatives.
Sarah was of two minds over her dilemma: she didn´t know if she wanted to spend her savings on a new car or on a trip.
*In two shakes of a lamb´s tail: quickly and easily.
When the teacher asked a question, Mary raised her hand and gave her an accurate answer in two shakes of a lamb´s tail because she´s very smart.
*To kill two birds with one stone: to complete two goals with one action.
Do you want me to pass by the drugstore for you? No problem, I have to go to the bank and the drugstore is on my way. I can kill two birds with one stone.
*To wrongs don´t make a right: doing something bad to someone just because he/she did something bad to you doesn´t fix the situation.
If I were you, I wouldn´t do this to Jim just because he´s harmed you. You know two wrongs don´t make a right, don´t you?
*Two´s company, three´s a crowd: you should´t go out with a couple of friends on a date if you´re unaccompanied.
My brother and his girlfriend keep inviting me to hang out with them, but I say two´s company, three´s a crowd! I don´t have a boyfriend!
*The three R´s: The basis of important skills: reading, writing and arithmetic.
Once we learn the three R´s in school , we apply them all the time in life.
*To give three cheers: to applaud or shout encouragingly and/or enthusiastically.
My math teacher gave me three cheers for doing so well on my last exam.
*To be at sixes and sevens: used to describe a state of confusion or disarray.
When our boss finished explaining how he wanted the job done, my coworkers and I were at sixes and sevens because we simply couldn´t get the main idea of it.
*Six of one, half a dozen the other: to see very little difference between 2 things.
If we do it your way or mine, to me it´s six of one, half a dozen the other. The result will be almost the same.
*To be in seventh heaven: to be extremelly happy and excited.
I was in seventh heaven when I finally got that promotion!
*To be on cloud nine: similar to "in seventh heaven", to be very happy.
Ever since Anne started dating she´s been on cloud nine. She´s happy all the time!
*Nine out of ten: almost all, the majority of a group.
Nine students out of ten get a job before they graduate.
*Nine-to-five jobs: a job with normal daytime hours.
I wouldn't want a nine-to-five job. I like the freedom I have as my own boss.
*To dress to the nines: to wear fancy or formal clothing.
You don´t have to dress to the nines to go to the party, it´s pretty informal.
*A hundred to one shot: very slight/difficult chances.
Mona told me she´s got that job she applied for last month. She didn´t get her hopes up because she thought it was going to be a hundred to one shot due to the huge number of applicants.
*To catch forty winks: to take a nap.
My dad likes to catch forty winks before dinner while he watches TV.
*At the eleventh hour: at the very last minute.
At Christmas time we usually buy all the gifts at the eleventh hour but places are still crowded.
*My lucky number came up: it was my turn to get lucky, something good happened to me.
After years waiting for such a great job opportunity, my lucky number has finally come up! The manager of that multinational company gave me a call and said I got the job!
*At first sight: as a first impression, for the first time you see it.
I don´t believe in love at first sight. Do you?
*On second thought: when you think a little better about something.
We were going to buy that new TV set last month. On second thought, we decided to keep our old one and save a little.
*Second nature (to someone): easy and natural.
She´s always swum very well. Swimming is just second nature to her.
*Second to none: the best.
That new Mexican restaurant is second to none. I´ve never had such a great meal in my life.
*Sixth sense: strong intuition.
I like to drive with Lisa. She has a sixth sense for directions and always knows how to get to places. She never gets lost.
(For more idioms from numbers, check http://www.idiomconnection.com/number.html)