Why more matter still left after collision with anti-matter? Question implies all, why is that? Why we exist even after equally creation of matter and anti-matter, any possible exception?
I presume you're asking about the mystery of the missing antimatter. This features extensively in the popular and scientific media. For example the CERN webpage on the matter-antimatter asymmetry problem is fairly typical. It says the Big Bang should have created equal amounts of matter and antimatter, but everything we see today is made almost entirely of matter. It goes on to say “something must have happened to tip the balance. One of the greatest challenges in physics is to figure out what happened to the antimatter”. 

I think it's something of a "clickbait" mystery I'm afraid, to try to curry favour with the paying public. Why do I think that? Because there’s baryon asymmetry, where we see lots of protons but hardly any antiprotons, and there’s also lepton asymmetry where we see lots of electrons but hardly any positrons. And they match. Take a look at positronium. It’s “a system consisting of an electron and its anti-particle, a positron, bound together into an exotic atom”. The electron is matter, and the positron is antimatter. Positronium however is neither matter nor antimatter. It’s both. It’s an exotic atom. Now see page 314 of photon and electron collisions with atoms and molecules edited by Philip Burke and Charles Joachain. It says “the positronium atom thus created is in essence a very light hydrogen atom”. So positronium is both matter and antimatter, and it’s like light hydrogen. 

The clear inference from that is hydrogen is also a combination of matter and antimatter. We say the electron is matter, and the proton too. But why? Surely since the proton is more like the positron than the electron, we ought to say the proton is the antimatter. Like this:



That would mean antimatter is a lot more common than people say. The proton mass is 1836 times the electron mass. Which would mean that weight for weight, 99.95% of everything around you is made of antimatter. Where’s all the antimatter gone? Nowhere. Because it’s hiding in plain sight. Because truth be told and by and large, you are made of it.