Often times having a hard time with math is more the fault of the teachers than your own. And I am saying this not as someone struggling with math but as someone who has surpassed his older brother who is 9 years older in his college math and help him grasp it on a regular basis. It's really important that math is taught the right way to children and if you were taught the multiplication table then chances are you had a very bad math teacher. I at least would never dream of teaching a child to work with numbers in that manner.

One of the things I would do if I were you is to condition yourself to working with small numbers quickly by making yourself do math even when it's not needed. Basically just play around with numbers when you're not totally focused on something else. For example if you are watching a video then look at the length of the video and try to figure out how many seconds it is, like if a video is 4 minutes and 35 seconds you split the 4 minutes into 240 seconds and add the 35 extra seconds for the total of 275 seconds. Or if you're looking at the clock then add the hours and mintues together, like my clock is telling me it's 19:14 then just something as simple as 19+14 = 33. You're not doing anything important, or doing any sort of grand math or even correct math in some cases, like why would you add hours and minutes together as if they represented the same value ? But you are however making yourself work with numbers and that I think is something that defines a lot of those that eventually become very good at working with basic math. Very much like when you're learning to read you start trying to read every little thing and all of a sudden you're 19 and you realize you're still reading most everything your eyes come across no matter how miniscule they may be. Like no one 'needs' to read "Coca-Cola" when they see a bottle of coke or an advertisemant for it, but you do it anyway out of habit. (Or at least I do...)

So yeah, just play around with math really, no matter how miniscule it is if you see numbers then do something with them, in fact especially if it's miniscule, add them, subtract them, multiply them, split them or whatever, just do basic math a lot.