Is anyone else basically a drooling retard when it comes to even simple mental math? Please tell me I'm not alone...

Is anyone else basically a drooling retard when it comes to even simple mental math? Please tell me I'm not alone. I've even forgotten my times tables for the weird ones like 7*8, I think I need to go back to third grade...

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amazon.com/Secrets-Mental-Math-Mathemagicians-Calculation/dp/0307338401
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amazon.com/Secrets-Mental-Math-Mathemagicians-Calculation/dp/0307338401
You will probably enjoy this book. You can practice times tables at the same time you are trying out these tricks.

Lol I'm literally reading that book right now and having a hard time that's why I made this thread.

Me

I often get corrected by cashiers because I gave them the wrong amount of money even though I do math the whole day.Its pretty funny,

I relate to this picture so much. I always feel that if there is a more abstract path, you are wasting your time developing a concrete theory.

There are a lot of mental math books out there and you should give those a look too, since I think you're supposed to pick and choose from the techniques you're most comfortable with. What helped me get over a few mental barriers with addition tables was Freaking Math.

Casually do mental math for practice. Get a good feel for the numbers. Find the tricks to playing with multi digits

I literally do not know what 8 x12 is.

It's funny because I remember my times table in chinese (memorised since I was 7) and to the day haven't forgotten them. I think our snappy language just makes it easier to remember than in English.

I'm not very good at mental math, usually. I've gotten a lot better at it with practise, though. I don't have my times-tables memorized, but I can do simple ones fast, and I can do 'complicated' ones pretty quickly by breaking it into simple ones. For example, 7*8 is equal to (7 * 10) - (7 * 2), 70 - 14, which is the same as 60 - 4, which is 56.

It's nearly a multiple of 10, my man.
Just do 8x10
then do 8x2

I don't think he wants to memorise them, that's basically useless. He wants to get good at mental calculation.

nice common core bro

I'm good with simple math.
I have forgotten how to do most anything beyond simple math though.

>7*8

That was always the hardest one to remember for me too. Interesting.

You do not "memorise" the multiplication table, you memorise rules of your base system and do the calculation in your head.

This is why western education sucks nowadays.

What you do is solve the problem in your head whatever way you like it.

Let's take your example of 7 * 8, these are possible ways to do it:

A)

1) You know that multiplication by 10 is just one extra 0 added, so you know that 7 * 10 = 70,

2) You know that 7 + 7 = 2 * 7 = 14

3) You substract 14 from 70 and end up with 56

or B)

1) You know that 7 * 8 = 7 * 2 * 2 * 2 = 14 * 2 * 2 = 28 * 2 = 56

wut
just do it like this if if you don't remember: 7*9-7 (7*9 naturally being 70-7)

Wrong, you memorize single digit products because it's more efficient. Subtract 14 from 70 and end up with 56? Don't be an idiot that's like 4 steps. Please learn something about computational efficiency

I got a problem wrong in my precal class a few years back because I thought 9*4 was 32. After that, I started using my calculator for everything, even really simple calculations.

I've been disenfranchised from math for a while. I'm getting back into it now and I'm learning baby logic. I've noticed that I can fill out a truth table for anything I come across in my "mental whiteboard" pretty quickly. Is this an implication of my ability?
As a child I was considered very gifted in school before I stopped participating(which happens to coincide around the time I started to be "taught" prealgebra and was the same way with arithmetic.

Nah dude, I just did 8 * 8 = 64 then add -8