 So I teach my kids math I recently told them this trick for adding numbers together really easily when you're either not good at Doing math in your head, or if you're trying to focus on one thing and you need to do some math without taking your mind off This or whatever or you just need to add some freaking numbers together without making any mistakes at all And I realized even though this is something I came up with when I was a little kid Something I still use today even though I'm very good at mental math now the problem is one little mistake can really mess up What you're doing so here's the trick? Say you're adding a whole bunch of numbers together Say you have a one plus a one plus a one plus a one plus a one plus a one plus a one plus a one This is really easy to add together right just go one two three four five six seven dancers totally seven there's seven of those But all the numbers aren't so simple right? What if you're adding twos together? It's not like the two just has like two spots you can count unless You pretend there's a dot there and a dot there you pretend there's a dot there and a dot there then you can go Okay, two three four five six seven eight nine ten eleven twelve thirteen fourteen and like a monkey could add like this and You like the things it doesn't take any any mental Power to do this you don't have to take your mind off other things you're doing and It's super easy to not make any mistakes, and that's why this is so useful So threes threes should be pretty obvious. They have a dot there a dot there a dot there So say say you want to add these three numbers One two three four five six now fours Four points one two. Oh actually no I make them I make them here. Yeah, if you get that one That's how I do it one two three four so one two three four five six seven eight nine ten five One two three four five sixes Sixes start to get a little bit funny because we start getting into higher numbers now, but two dots On every level so one two three four five six seven eight nine ten Eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen twenty twenty one Seven is pretty easy to figure out. There's three dots along the top, and then this this line's longer, so it has four One two three four five six seven eight Let's put our eight over here Eight each circle has four dots one two three four one two three four And then nine Trying to make a nine like like on a typewriter, but anyway, it's got three dots here three dots here, and then three dots here So when you have a whole string of numbers you're trying to add together and you're on some work site You don't have your calculator or smart phone or whatever you just need to scribble some garbage down on a piece of paper Add some numbers together and reliably get like as close to a hundred percent correct without Making any mistakes. This makes it super easy. So let's say we're adding all these numbers together One two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen twenty twenty one Twenty two twenty three twenty four twenty five three six twenty seven twenty eight twenty nine thirty through one through two Three three four three five three six three seven three eight three nine forty forty one forty two forty three forty four forty five I counted that right I think I counted that right anyway, and zero obviously has nine so You know once you once you get used to where the dots are, you know You don't have to write the dots on it. I know a five is one two three four five I know Seven is one two three four five six seven And that's that's my math trick and it works for subtraction, too You know let's say I got a seven and I want to take a five off and I'm not say I'm not very good at math I can I can start with seven and then go six five four three two seven minus five equals two. Oh Man a bunch of numbers now how my calculator all right seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen Well, that's ten obviously eleven twelve thirteen fourteen fifteen sixteen seventeen One two three four five six seven eight nine Oh, that was a piece of cake