Correcting yourself out loud while still speaking is rare because it briefly makes you look unreliable. What it actually signals is that you are tracking the truth faster than you are tracking your image, which lands as unusual and quietly impressive. Most people prefer to let the slightly wrong version stand and hope it does not come up again.

Use it next time a number or a detail is off as it leaves your mouth. Say the correction plainly and carry on without apologising for it. The people listening start trusting everything else you say a little more.